Why do LEGO bricks turn yellow?

LEGO bricks are made of Acrylonitril-butadieen-styreen or for short ABS. ABS is very cheap and very sturdy. It is however flammable (they add product against it) and also very sensible to UV-light, oxygen, moist and heat. If LEGO bricks are exposed too much to these elements, they will turn yellow. So best to keep your used LEGO dry, dark,  temperate and preferably wrapped in a plastic bag to keep out oxygen.

But there is  good news for those precious sets that were not kept in that manner.

I recently bought a second had 6339-1 Launch Pad from a woman on a second hand site in "GOOD" condition, but turned out it was completely yellowed. It was not possible to get refund so I started experimenting after looking up stuff at google.

Materials

• Hydrogenperoxide: It is because of my ex that I found out what exactly it was. It is used to bleach hair so if you go to your local Brico, not going to find it. You can get it at stores like Kruidvat or in a pharmacy. As test, I took a 3% Hydrogenperoxide mixture like this one.
• Vanish Oxy: A stain remover. Reacts with the hydrogenperoxide. Can be found about everywhere. You can get it at Kruidvat
• A container: The smaller the better. Perhaps also best to take one in white or transparant so you catch the most UV-rays.
• The sun: You'll need to have a sunny day. UV-rays are a necessity for this to work correctly.
• Time: Count 8 hours for the bleaching process to take effect.

Results

I tested in on a clouded day but I was too anxious to test so went along just to see what it gave.

This is the rest of my materials. As said a 3% hydrogenperoxide mixture and sone Vanish oxy that I first dissolved in a very small quantity of water. I left the bricks to sit in the solution for about 8 hours. During those 8 hours I spooned it every hour about.

Result

So the white bricks did have a noticeable improvement. Grey bricks stayed about the same. But it does work. I will repeat this experiment on a more clear day. Normally saturday is forecasted as a sunny day, but you never know in Belgium. I will also take a 10% solution that I bought at the pharmacy. It is quite alot more expensive (paid 20€ for half a liter) tho so I hope it doesn't differ much from the 3% solution. I do believe the sun is the deciding factor on this one.

The bricks themselves still feel flexible and sturdy, the shape and form seems unchanged.

I'll post another update as soon as I get more results.

If you want the Dutch version go here.

Edited October 7, 201510 yr by Neosphinx

I have a better method:

I take a big bucket or any other big container with the right size for the bricks, put the bricks into the container and then I use white color and fill the bucket with it

No just kidding ;-) Never done such a thing *g*

 

Thanks for experimenting so we don't have to! ;-)

I have not seen the results, but someone I dealt with in the past used polident which apparently worked incredibly well.

I have not seen the results, but someone I dealt with in the past used polident which apparently worked incredibly well.

Well, if you need to repair your  bricks, here you have some proof of results so a method that works.

Just a quick note before my  tests on saturday with 10% hydrogenperoxide. Use the correct safety equipment. Good gloves and safety glasses. That **** can be dangerous.

So I actually had to wait a bit to get a sunny day but the results are good. I did not add the vanish oxy this time. Just hydrogenperoxide 10%

Before (horse is reference)

After. The little cabinet on the top is from a new set.

The gray parts have not changed alot. Probably were not as affected by the elements as the white. There is only 1 part in the whole bunch that was still a bit yellow. Perhaps if there would be more sun, it would have been ok too. Anyways, I am pleased with the overall result.

I did pay about 20€ for 0.5 liter of hydrogen peroxide so kind of overpaid for this set but it was worth the experimenting.

 

Edited October 19, 201510 yr by Neosphinx

I actually had to do this over the weekend as well as a Bricklink part I got in light bluish grey came with a nice brown hue to it.  Getting tired of crappy parts being sent to me, but that's for another thread.  Put it out on the deck with H2O2 and some Oxy Clean for the afternoon and it looks brand new again. 

Where is the horse in the "after" picture as reference? :-P

Nice though!

I did this a few years ago with some Star Wars figures and G.I.Joes. It was pretty effective, but the yellowing does begin to return after a few years, even in the dark.

Ive actually been doing this over the weekend with a used 6211 I bought. It was in pretty bad way, some pieces very discolored. Anyway its been sat in a 3% solution, for 3 days, been giving it the occasional stir.

The results have been disappointing, like you said I think the UV levels are the deciding factor and its been really overcast here. You can re-use the solution a few times before it looses its potency, something to bear in mind before you throw it out. I will have to wait for some better weather before I can retry.

 

Where is the horse in the "after" picture as reference? :-P

Nice though!

Somehow I knew someone would bring up the horse. And funnily enough, I even knew it would have been you lol. Sold the horse in the mean time

Ive actually been doing this over the weekend with a used 6211 I bought. It was in pretty bad way, some pieces very discolored. Anyway its been sat in a 3% solution, for 3 days, been giving it the occasional stir.

The results have been disappointing, like you said I think the UV levels are the deciding factor and its been really overcast here. You can re-use the solution a few times before it looses its potency, something to bear in mind before you throw it out. I will have to wait for some better weather before I can retry.

 

Yes, very much so. UK has same weather as here and past few days have been less than opportune to do this. I did it about a week or 2 ago and got lucky there was 1 good day. Of course you can also try a UV lamp, but that involves extra cost :-/

Yes, you definitely need the UV to help reverse the effects that it caused in the first place.

Naturally I usually see this on white bricks but was wondering it works the same/doesn't damage colored ones? We have an -eeck- Green Grocer whose gray bricks have off coloring.

Naturally I usually see this on white bricks but was wondering it works the same/doesn't damage colored ones? We have an -eeck- Green Grocer whose gray bricks have off coloring.

It should have the same effect on gray bricks. I added all of the gray bricks from my set too and none were damaged. The result however was not that much different but they were not very yellowed to start with

Naturally I usually see this on white bricks but was wondering it works the same/doesn't damage colored ones? We have an -eeck- Green Grocer whose gray bricks have off coloring.

With G.I. Joe and Star Wars, the blue and grey ABS plastic returned to near their original colors.

http://brickzz.be/brickzz/index.php/menu-artikels/lego-algemeen/386-vergeelde-lego-steentjes-restaureren

 

Waarom verkleuren de LEGO steentjes

^.^ I like the word "verkleuren" somehow

so is this article actually from you?

For me it's always funny to read dutch as I kind of understand it and at the same time I don't ^.^

And the words seem to be so much cuter than in other languages *g* (like swiss german also sounds adorably cute).

I actually had to do this over the weekend as well as a Bricklink part I got in light bluish grey came with a nice brown hue to it.  Getting tired of crappy parts being sent to me, but that's for another thread.  Put it out on the deck with H2O2 and some Oxy Clean for the afternoon and it looks brand new again. 

I'll have to give this a shot.  Usually, if I'm sorting through parts and I'm not satisfied with the color, I just toss them in the trash.

I'll have to give this a shot.  Usually, if I'm sorting through parts and I'm not satisfied with the color, I just toss them in the trash.

So do I unless it's a part that cost quite a bit, which it was in this case.  Cheap pieces are not worth the time.  Keep it out all day in the sun, it's pretty amazing.  I think with this being a newer part and not an old grey/blue/white it worked better because the "stain" hadn't been there as long.  My results with old white pieces has been pretty good as well.  I've heard you can do it with straight H2O2, but I've always used the Oxy clean as well.

http://brickzz.be/brickzz/index.php/menu-artikels/lego-algemeen/386-vergeelde-lego-steentjes-restaureren

 

Waarom verkleuren de LEGO steentjes

^.^ I like the word "verkleuren" somehow

so is this article actually from you?

For me it's always funny to read dutch as I kind of understand it and at the same time I don't ^.^

And the words seem to be so much cuter than in other languages *g* (like swiss german also sounds adorably cute).

Yeah is my article and my site. Prefer writing in mother language because i get tired of correcting english mistakes so just resumé here.... IT WORKS

Wow! In that case: Nice site!

Now that I know you didn't only write this in english for us but rather translated it after you wrote it in dutch: Thanks!

Looks like this topic has been off the range for a while but after buying a bunch of bulk lots in the last few months needed to look into a fix for a bunch of yellowed and discolored bricks. So far the results have been pretty nice....

I've found that a solution of 3% peroxide and sufficient sunlight (even works through a window, unless you have a uv filter on it) brightens the whites up considerably, like new. I've tried it on purples, pinks, old grey(light and dark) and some tan and its made the bricks usable, where as before they'd have gotten pitched. The only color I haven't attempted yet is red and hopefully this weekend will be nice to do so............. Cheers!

14 minutes ago, longshot said:

Looks like this topic has been off the range for a while but after buying a bunch of bulk lots in the last few months needed to look into a fix for a bunch of yellowed and discolored bricks. So far the results have been pretty nice....

I've found that a solution of 3% peroxide and sufficient sunlight (even works through a window, unless you have a uv filter on it) brightens the whites up considerably, like new. I've tried it on purples, pinks, old grey(light and dark) and some tan and its made the bricks usable, where as before they'd have gotten pitched. The only color I haven't attempted yet is red and hopefully this weekend will be nice to do so............. Cheers!

I wrote about it back in January. I've had problem with red or orange paint on Hasbro parts.

 

Funnily enough I watched an old video by jang last week suggesting that same method, I was going to try it on some of my old sets. Good to hear you had good results from that method.

I've used food grade H2O2 that was 25% and cosmetic grade that was 6% and 12%. They are all about as effective long term even the standard 3%, but the higher concentration worked faster.