Are you troubled by yellowed, lifeless Lego?

There I was, idly scanning eBay for Lego baseplates to maybe give to one or another child for Christmas (HOW CAN THEY NOT MAKE CRATER PLATES ANY MORE WHY WAS I NOT CONSULTED), and I noticed that most, if not all, of the plates on offer weren't very close to their original colour.

This reminded me of a thing from the other month about de-yellowing the casings of old computers and video games.


If you don't want to paint over the yellowed plastic, you can soak it in a hydrogen peroxide solution, with a dash of one or another kind of bleach. (Note that the popular "oxygen bleach" products are based on sodium percarbonate, which when added to water just gives you hydrogen peroxide plus washing soda.)

If you want to get fancy, you can make a gel concoction dubbed "Retr0bright", which'll stay where you put it. So you can bleach things without having to remove all the electronics so you can dip the casing, or bleach the outside of a thing but not the inside, et cetera.

Apparently even plain few-per-cent peroxide will often do the job if you leave the pieces to soak overnight. If you want faster results, you need 10%-to-20% peroxide, which you may or may not be able to get from a pharmacy.

(I must, at this juncture, digress and recommend Armadillo Aerospace's old video - 56Mb MPEG here - of what happens when you put high-test rocket-fuel-grade hydrogen peroxide on various common substances.)

Does this technique, I wondered, work on Lego?

Apparently, yes, it does! Even on clear pieces!

(Bleach can apparently attack the paint on some printed bricks, though.)

I don't think this will actually do the plastic any harm, either. Or any more harm, anyway. The reason why plastic discolours in the first place is because something - ultraviolet light and/or atmospheric oxygen, usually - reacts with one or more of the constituents of the plastic. The material that yellows may be the polymer itself, or it may be flame-retardant additives, or plasticiser, or something. In any case, bleaching already-damaged substances back to white shouldn't do any more damage.

[Update: I just remembered that a couple of years ago I wrote this piece, about the making of Lichtenberg figures in clear acrylic. It involves a rather unusual way to discolour plastic.]

You don't have to bother with this at all, of course. A yellowed Amiga 500 is still an Amiga 500, and yellowed Lego is still Lego. Some builders have even...

'Weathered' Lego 'mech

...used yellowed pieces to "weather" models!

8 Responses to “Are you troubled by yellowed, lifeless Lego?”

  1. Erock666 Says:

    Any word on how this works on nicotine stains? My mom smoked like a chimney when I was a kid...

  2. Daniel Rutter Says:

    Bleach ought to work on smoke-stains, too.

    You've probably actually got a combination of smoke-stains and ordinary yellowing. The smoke stains may or may not have penetrated enough to really need bleaching rather than ordinary soap-and-water cleaning.

    (Lazy version of the latter: Tie Lego pieces up in sock or similar permeable bag, pop in washing machine or dishwasher. If you don't have a dishwasher with a special Lego cycle, you should use the "eco" setting that doesn't bake everything dry at the end, or just interrupt it when it gets to the drying stage. Large pieces like baseplates should probably be cleaned without machine assistance.)

    An ultrasonic cleaner would probably also do some good against smoke stains, with ordinary water and a little detergent. It now occurs to me that you could use a bleach solution in an ultrasonic cleaner too, which would very probably accelerate the process considerably. I don't know if anybody's tried that, but I'll see if I can dig up some yellowed pieces and give it a go.

  3. nynexman4464 Says:

    This is awesome news. My parents have finally decided to get rid of all my old Legos, and told me to take them. I was hoping there might be something I could do about all the old whites that have seen better days. I like the the 'weathered' concept, but I tend to prefer more 'prestine' looking models.
    Now if I can figure out how to get all the cloudy, scratched up windshields looking good again, I'd be in good shape. :)

  4. Stark Says:

    nynexman - you might want to try a very fine polishing compound and a very soft cloth on some of those scratched up pieces. I've had good luck on minor scratching and just plain clouding of Lego and other clear plastics (Ipod screen face comes to mind) using Brasso and a micro fiber cloth. Try it on one piece, see if it works, if not, you've not really done much harm since it was already damaged. Keep in mind that this is a destructive process - you will be removing very fine layers of plastic... so do it by hand and not with, say, a random orbit buffer. Ahem.

    Dan - you really freak me out man. Multiple times over the last few years you seem to have been reading my mind by posting topics directly related to things I was just about to research. In this case, I just came into possession of a circa 1980 Millenium Falcon ( which lived in a closet for the last 25 years and has some serious age related yellowing issues. My 4 year old is big into Star Wars and so it's an excellent xmas present candidate but I really did want it looking better than it does... I know what I'm doing tonight!

    So, in short, thanks for the info and get outta my head... or please remove your surveillance equipment form my home. Either way.

  5. whitelined Says:

    I'm sure I have a lunar base plate, I'll have to dig it out of my lego box, which is at my mum's house, and send it to you if I find it.

  6. Stoneshop Says:

    Dan, I must congratulate you. Even in a post about the nerd's lowly household chores, cleaning up computer cases and Lego bricks, you manage to put a video about things catching on fire. Ever thought about applying for a job at Mythbusters?

  7. FuzzyPlushroom Says:

    So, instead of/in addition to the traditional ultra-fine-grain wetsanding method, d'you reckon this'd work with yellowed/clouded polycarbonate headlight lenses? I know Lego bricks are made from ABS, but this also seems to work on PVC and such, and the clear Lego give me hope. (I ask, of course, because my car's old enough to drink, even here in the States, and the headlights have gotten rather excessively dim.)

  8. Daniel Rutter Says:

    I think it'd just turn your yellow clouding into colourless clouding.

    The clouding is damaged plastic, partly from mechanical scratches and partly from chemical causes. You could maybe bleach it and then fill all the scratches with some crystal-clear resin or silicone goop or whatever, but I think the best you could actually achieve by doing that is a nice-looking finish that still doesn't actually transmit light from behind it very well.

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