I've been looking at the safest ways to restore the color of the Mac without over bleaching the unit or leaving streak marks.

Because the inside of a Mac 128/512/Plus is coated with a conductive covering, I want to avoid submerging the case into hydrogen peroxide as it induces rusting/oxidation. I also want to avoid buying gallons of hydrogen peroxide.

The two methods I tried were using just the sun (nothing else!), and a hydrogen peroxide cream. Here is a before/after gif of a platinum bezel using the two methods.

Results Overview

As seen in the gif, the center bezel is before and after. The bezel was place between a lightly yellowed bezel on the left and a heavily yellowed bezel on the right just for reference.
The sun was able to restore the color to a modestly yellowed state.
The creme did a much better job and was able to restore the color to a very slight yellowed state.
I was impressed with both results in general

Please note that the cream did NOT over brighten the bezel! From the area under the logo, you can see that the original color was even brighter.


On the negative side for the cream. the bezel color was not evenly restored. On the left side of the inward CRT bend, there's extra yellowing, as highlighted in the image below. This is partially because it's difficult to get all the edges an equal amount of sun in such a short amount of time.

Sun Method

Bezel was placed outside in the sun, in the middle of January, every day between 11am and 4pm (I get limit sun due to surrounding buildings). 2 of the days were sunny and 3 days were cloudy. Temperature was cold, about 6*C/43*F every day. I did check on it everyday and on cloudy days the bezel would get brighter as well. I would place the bezel at slightly different angles every day to ensure all edges got some sun. Only the top side came out a bit darker, but this can be easily fixed by placing it at an angle to focus on top side.

Below is an image of 4 Mac Plus platinum bezels. From left to right:
1. Original Color
2. Brightened via cream, original color can be seen where the logo was removed.
3. Brightened via sun for 5 days
4. Heavily yellowed bezel (right side bezel from above gifs)



Lastly, I'd like to note that the 5 days of sun had no visible affect or discoloration on the badge, however I'm sure that if I did leave it out for a couple weeks it would.

Cream Method

I followed the method described in this youtube video.
Recipe (note this makes enough to do at least 5 macs!!):

• 500ml 3% hydrogen peroxide
• 1 tablespoon Xanthan Gum
• 2 tablespoons Glycerin
• 1/4 teaspoon Oxiclean power

I used a hand mixer to to mix everything, consistency came out very similar to video. I tried to re-apply cream every 15~20 minutes; I'd recommend every 15 as after 20 minutes it was starting to get a bit hard. It was in the sun for just about 2 hours.

Conclusion

The sun did a surprisingly really good job! However it seems you'd probably need to leave it out in the sun for a month if you'd like to remove most of the yellowing.
The cream also did a great job, but it can be hard to get even results on a heavily yellowed bezel.
My final suggestion would be to leave the case out for 1~2 weeks in the sun, and then follow up with a 1 hour cream treatment to get that extra final mile.

>> pocketscience said:

I was skeptical, but you can see a difference after only a few hours. After a few days it makes a massive difference per my earlier photos. I'm sold. However I received a ruined 400K external drive from @Elemenoh - someone had peroxided it very poorly. The sun is not making one iota of difference to that sadly. Click to expand...

I have the same experience. A keyboard which was looking beige, turned to more or less its original color after a few days of exposure to sunlight. The same with a yellowed CC case.
Not as quick and spectacular as retrobrighting, but way less intrusive.
Besides, I don't mind seeing some patina on vintage machines. My motto is more "preserve" rather than "restore", so sunlight is just what I need (and that's true beyond computers).

>> Paolo B said:

My motto is more "preserve" rather than "restore", so sunlight is just what I need (and that's true beyond computers). Click to expand...

That is a good one, @Paolo B! :)

So, I came across this YouTube video where a person retrobrited the Mac Plus in clear plastic tubs with the Salon Care 20 Volume Clear Developer mixed in water. Left out in the sun for about two hours, and it worked great.

I wonder if you tried retrobriting submerged in water and the sun sans any hair salon or other chemicals?

I don't see any value of putting it inside a plastic container in water and then just using the sun. Why not just use the sun. Any plastic tub will interfere with the light from the sun, so it's not going to be as effective as just in the sun. As I said before these machines are 30+ years old. Why rush.

>> retr01 said:

Hi @catboyjack , did you do the instructional video and post it on YouTube? Click to expand...

I never got around to it. Lot of IRL stuff happened around the time I made that post, but I hope to *eventually* get to it! :)

Howdy everyone!

I *finally* finished pre-production for the most part and started filming the documentary I promised on my retrobrighting procedure.
I'll try my best to have it out by the end of the month.

In the meantime, I treated the reset/interrupt switch to give a demo of the contrast between the current yellowed state of my SE and the original Platinum color.

>> retr01 said:

I wonder if you tried retrobriting submerged in water and the sun sans any hair salon or other chemicals? Click to expand...

I recently tried hydrogen peroxide mixed approx 1:5 with demineralized water for whitening some super yellowed keyboard and MO drive case.
It works, but getting uniform treatment for complex shapes requires continuous attention for avoiding over / under exposure of some areas.
I don't think I will do it again.

>> Paolo B said:

I recently tried hydrogen peroxide mixed approx 1:5 with demineralized water for whitening some super yellowed keyboard and MO drive case. It works, but getting uniform treatment for complex shapes requires continuous attention for avoiding over / under exposure of some areas. I don't think I will do it again. Click to expand...

Did you use the sun?

>> wottle said:

Did you use the sun Click to expand...

Yes, of course. A scorching sun. Took a few days. The lettering on the keys got slightly washed out, too, so I guess I should have paid more attention. Anyhow, I am not a fan of retrobrighting, so I consider it a one off trial. As I wrote, surprisingly enough, plain exposure to direct sunlight seems to work magic if you are sufficiently patient. That's just fine by my tastes.

>> Paolo B said:

Yes, of course. A scorching sun. Took a few days. The lettering on the keys got slightly washed out, too, so I guess I should have paid more attention. Anyhow, I am not a fan of retrobrighting, so I consider it a one off trial. As I wrote, surprisingly enough, plain exposure to direct sunlight seems to work magic if you are sufficiently patient. That's just fine by my tastes. Click to expand...

I haven't had much luck with sun alone, especially since I feel like that heat and humidity for long periods is not the best. I think the "low and slow" method of using lower powered UV LED lights combined with peroxide creme, wrapped in plastic wrap to keep the creme from drying out has never hailed me. Leave it overnight and unless it is extremely orange, it will be back to close to the original color in the morning.

>> wottle said:

I haven't had much luck with sun alone, especially since I feel like that heat and humidity for long periods is not the best. I think the "low and slow" method of using lower powered UV LED lights combined with peroxide creme, wrapped in plastic wrap to keep the creme from drying out has never hailed me. Leave it overnight and unless it is extremely orange, it will be back to close to the original color in the morning. Click to expand...

Likewise

Generally though I discourage the use of plastic wrap or just "setting it and forgetting it".
I believe for the best results it's best to constantly monitor the plastic, but not everyone can do that.

That's why I paint the cream on every hour and leave it exposed in my UV box, but since I don't have much time during the week I have to keep my projects for the weekend.

>> catboyjack said:

Likewise Generally though I discourage the use of plastic wrap or just "setting it and forgetting it". I believe for the best results it's best to constantly monitor the plastic, but not everyone can do that. That's why I paint the cream on every hour and leave it exposed in my UV box, but since I don't have much time during the week I have to keep my projects for the weekend. Click to expand...

Interesting. I've never had any splotchiness with LED lights and plastic wrap. I have only seen inconsistent results with wrap when exposing it to direct sunlight. And I feel like it's due to focused, high intensity sunlight and cooking some parts of the peroxide. I've retrobrighted probably 20-25 machines with this approach and haven't had one go bad. I've had to do a second session on some very bad machines, but even those were consistent, just still yellowed after the first session.

Have you had issues with plastic wrap inside with UV LEDs? I also am very conscious to try to minimize too many layers of plastic which most being a single layer, but occasionally being 3-4 if there's a corner where there's excess that needs to be folded over. And I always make sure it's air tight so that it stays wet throughout the 9-12 hours I leave it in the box. So if you've had bad experiences, it would be good to get the details so we know what things to avoid for people looking to get into retrobrighting.

I also had best and fastest results painting every 20-30 minutes with cream, but I use it 50% diluted in water.
But I'm a bit wary about using this on the most valuable items... for that I use submersion and UV LEDs, it's much slower, but I feel like I have more control on it.

>> pfuentes69 said:

I also had best and fastest results painting every 20-30 minutes with cream, but I use it 50% diluted in water. But I'm a bit wary about using this on the most valuable items... for that I use submersion and UV LEDs, it's much slower, but I feel like I have more control on it. Click to expand...

I agree. The problem with the sun is, whether people realize it or not, the intensity varies greatly depending on where you do it / what time of year. So getting it right requires a good deal of babysitting. Using the LED box is much more forgiving and the difference of leaving it in the box for 8 hours vs 12 hours isn't very different. Meanwhile, my early days of retrobrighting I left my 5400 out in sun for a few hours when I forgot to pull it out of the sun and had to go to my daughter's soccer game... Well, there's a reason why I have a thread on here where I made it black to match the directors edition.

>> wottle said:

I agree. The problem with the sun is, whether people realize it or not, the intensity varies greatly depending on where you do it / what time of year. So getting it right requires a good deal of babysitting. Click to expand...

Yes. NASA has some information on how the various bursts from the Sun can affect some things here on Earth. The Earth's magnetic fields help a lot, blocking much of the radiation and other adverse effects. Yet, there is global warming going on that seems to affect the Ozone layer, and I think it does vary to some degree on some days and others. It makes me wonder how the movie Finch on Apple TV may happen if there is not enough action to reverse it.

>> wottle said:

Using the LED box is much more forgiving and the difference of leaving it in the box for 8 hours vs 12 hours isn't very different. Click to expand...

Yep. Controlled.

>> wottle said:

Meanwhile, my early days of retrobrighting I left my 5400 out in sun for a few hours when I forgot to pull it out of the sun and had to go to my daughter's soccer game... Well, there's a reason why I have a thread on here where I made it black to match the directors edition. Click to expand...

*gasp* So, that's why. Was it too white, or what?

>> retr01 said:

Yes. NASA has some information on how the various bursts from the Sun can affect some things here on Earth. The Earth's magnetic fields help a lot, blocking much of the radiation and other adverse effects. Yet, there is global warming going on that seems to affect the Ozone layer, and I think it does vary to some degree on some days and others. It makes me wonder how the movie Finch on Apple TV may happen if there is not enough action to reverse it. Yep. Controlled. *gasp* So, that's why. Was it too white, or what? Click to expand...

Yes, too white overall, but also some pretty bad splotchiness where I think the peroxide dried out in the intense sunlight... However, it gave me the ability to risk painting it with little fear it would make it look worse.

>> wottle said:

Interesting. I've never had any splotchiness with LED lights and plastic wrap. I have only seen inconsistent results with wrap when exposing it to direct sunlight. And I feel like it's due to focused, high intensity sunlight and cooking some parts of the peroxide. I've retrobrighted probably 20-25 machines with this approach and haven't had one go bad. I've had to do a second session on some very bad machines, but even those were consistent, just still yellowed after the first session. Have you had issues with plastic wrap inside with UV LEDs? I also am very conscious to try to minimize too many layers of plastic which most being a single layer, but occasionally being 3-4 if there's a corner where there's excess that needs to be folded over. And I always make sure it's air tight so that it stays wet throughout the 9-12 hours I leave it in the box. So if you've had bad experiences, it would be good to get the details so we know what things to avoid for people looking to get into retrobrighting. Click to expand...

I personally never tried using plastic wrap with LED lights, mainly because I've had bad experiences with plastic wrap and sunlight. Never considered it, but I might give it a shot next time!

>> catboyjack said:

I personally never tried using plastic wrap with LED lights, mainly because I've had bad experiences with plastic wrap and sunlight. Never considered it, but I might give it a shot next time! Click to expand...

I only use that method now. It allows me to tackle things quickly because I can do it overnight and don't need to babysit. And as I said it's forgiving and I've not yet had anything come out splotchy. Let us know how it turns out. I've had so many people claim the plastic wrap is too dangerous, but I personally believe using the sun is the greater risk.

>> wottle said:

I only use that method now. It allows me to tackle things quickly because I can do it overnight and don't need to babysit. And as I said it's forgiving and I've not yet had anything come out splotchy. Let us know how it turns out. I've had so many people claim the plastic wrap is too dangerous, but I personally believe using the sun is the greater risk. Click to expand...

I'll give it a try with my SE face plate for the video, I plan on doing it tomorrow since I just took it fully apart.

>> catboyjack said:

I'll give it a try with my SE face plate for the video, I plan on doing it tomorrow since I just took it fully apart. Click to expand...

Also, I forgot to note that when I do the plastic wrap, I try to ensure I squeeze out any air bubbles under the plastic. I think large air bubbles could allow the peroxide to dry out, which could be the cause of some people's problems.