I have some LEGO bricks I would like to clean some old sets and parts I bought from Brick Owl.

So I would like to know what soap is the safest for cleaning the LEGO parts I was thinking maybe soft soap or something.

By the way, I won’t be cleaning printed or stickered LEGO.

  • What kind of dirt (in a very general sense) do you want to get rid of? In most cases hot water will do the trick. Oct 8, 2020 at 6:23
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    Does this answer your question? LEGO cleaning techniques and tools Oct 8, 2020 at 10:13
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    I just want to do a good cleaning because: a cat used the LEGO bucket for a litter box one time and my siblings have touched the LEGO
    – Justan
    Oct 8, 2020 at 13:11

2 Answers 2


The official guidance from The LEGO group suggests using a mild detergent.

Cleaning your LEGO® bricks is really easy! We recommend that you clean your LEGO® parts by hand using water no hotter than 104°F / 40°C and a soft cloth or sponge.** Higher temperatures may affect the quality of the parts. You can add a mild detergent to the water - please rinse them well with clear water afterwards and you're done!

A word of warning! Please don't put your LEGO® pieces in the washing machine or dishwasher, and don't try to dry them in the oven, the microwave or with a hair dryer. When the bricks get really hot they may change shape, which means they won't work anymore!

Cleaning your LEGO® bricks

In most cases warm water is enough to clean LEGO bricks, some soap can help remove tougher stains, dirt and smells.

Examples of mild detergent include liquid hand or dish washing soap, as opposed to things like bleach and ammonia which are irritating and corrosive to the skin which may damage bricks.

Mild detergent should be enough to both clean and sanitise.

  • What kind of mild detergent? Liquid or powder?
    – Justan
    Oct 8, 2020 at 13:12
  • I was wondering if dishwasher liquid would work like Dawn dishwashing liquid
    – Justan
    Oct 8, 2020 at 13:19
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    I'm assuming by mild detergent they mean liquid hand or dish washing soap, as opposed to things like bleach and ammonia which are irritating and corrosive to the skin which may damage bricks. Mild detergent should be enough to both clean and sanitise.
    – Ambo100
    Oct 8, 2020 at 14:37
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    Agree on not using anything dishwasher related. Washing machine, however, is fine in my experience as long as you keep to recommendations of not using strong detergent and the right temperature. I would suggest to clean tray for detergent from any leftovers and keep your bricks in mesh laundry bag. Delicate/silk washing programme is advised too.
    – Alex
    Oct 8, 2020 at 16:36

Dishwasher Powders - Nope! These contain abrasives that will scratch up your bricks.

Liquid Dish Soap - Probably anything goes here. Lemon scented bricks, Mmmmmmm!

Head soap - Most anything here, but avoid stuff like liquid lava w/ pumice.

Laundry Soap - Seems to work fine, I have filled entire wading pools with water, Lego, and laundry soap to clean vast quantities all at once. This is your economy of scale if you have to wash a lot efficiently.

Bleach & Water - Not a great solution, unless you are just briefly dunking it. Bleach will clean very well, but if you leave it soaking for hours or days, Lego slowly absorbs the bleach and swells very slightly causing the bricks to gain clutch power. Not a bad plan if you want to put some stick in your old bricks, but experiment carefully before you commit. This swelling doesn't seem to cause any long term damage.

H2o2 + Oxyclean - This will 'lighten' UV damaged bricks, but I haven't had much success with it. It takes a long soak to accomplish it, though. There are many pages on the Intarwebz talking about how this works.

Petrochemicals - These are in general risky, as they can act a solvents for ABS. Test before use. Except for....

Goo-Be-Gone - I have use this on all types of Lego, and it is perfectly safe to drench on. Great for getting rid of sticker goo.

Warm water is fine, but water > 130F starts to get risky, aside from burning yourself, thinner types of plastics start to bend and warp. Watch out for things like base-plates which are particularly vulnerable here.

Running Lego through a dishwasher is probably not a good idea, they generally use pretty hot water to kill germs, and the heat exposure isn't brief.

Also, be aware that Lego isn't one type of plastic. It is mostly ABS, but there are other things like windshields mixed in, along with differing formulas of ABS. Heat and chemical tolerances will vary.

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