Fingers crossed they don't.
I did a bit of research into how I could get the pieces white again. Finding links from The Brothers Brick
that then gave me a link to another site called Amibay where users restore old gaming consoles like C64's and Amiga 500's. I read through a lot of those pages looking at results.
So I then spoke to a few people who have done the Retr0bright treatment, who had mixed results. A couple said they have had no issues after the treatment and a couple said they came back yellowed more then they ever were. Some had use 12-35% solution hydrogen peroxide so I'm not sure if that had anything to do with the various results.
|What we purchased at our local Woolwoths.|
Before even attempting to use these products please wear rubber gloves and protective glasses and be safe!
I got my wife to take a trip to our local Woolworths to pick up some Faulding: Hydrogen Peroxide which is a 3% solution so I could give it a test run. We already had Varnish Oxy action laundry powder. I did my first test run on Friday just past with a piece with printing and a 4x4 plate.
I poured in about 75Mls into a small glass jar, just enough to cover the pieces and less then a 1/4 of a teaspoon of oxy action and stirred well till it was dissolved.
After about 3 hours in sunlight and keeping a very close eye on it, to make sure it wasn't doing major damage to the pieces. It was a success! The printing was intact and the 4x4 plate became white as ever! With no physical signs of any brittleness. They felt and looked like new.
Then the next day I did a larger batch of about 45+ pieces into a clear takeaway container with about 325Mls of hydrogen peroxide and a 1/4 of a teaspoon of oxy action and stirred well till it was dissolved. Then put in all the pieces and waited for about 4 hours in sunlight, checking in every hour to see how things were progressing. and here are the results...
They look like brand new again! Whether they stay that way only time will tell and I will update you if there are any changes to those pieces I "restored".
I hope I have explained this process easy enough for you to give it a try yourself. I am very happy with the results so far and I will be giving my 1980's LEGO the treatment in due course.
After 2 years and nine day thanks to a reader's comment reminding me about this post I thought I would post that very picture I took today.
The parts that I treated have reverted back to their yellowed state. :/
I never reunited these parts to their respective sets so it was easy to find as they haven't left my side on my computer desk.
Here is that photo...