Cleaning mold/mildew from Legos

Factual Questions
1

I have been a Lego fan for as far back as I can remember, and thankfully, my daughter has also picked up the habit. My mother was kind enough to rummage through her attic and find the tubs of Legos I had as a little KCB. They’ve been in her attic for better than 20 years, stored in open tubs and 5-gallon buckets. A cursory look at them shows mold and/or mildew covering most of the bricks. I’d prefer my little one not play with them in such a state.

How do I go about cleaning these? I could go the toothbrush route, but we’re talking tens of thousands of bricks. I would like to dunk or soak them in a 10% bleach or similar solution, then let them air dry. I’m sure that would kill the mold/mildew, but I don’t know if it would remove it. I am also concerned about the graphics that are printed on some of the bricks, I’d prefer it the cleaner didn’t strip those off. I figure the bricks with stickers will just have to get special treatment.

A quick Google search suggests using the dishwasher and laundry bags, but I’m not sure I want to subject my precious Legos to such a fate.

Any suggestions?

2

We certainly used to put ours in the dishwasher. Didn’t seem to do any harm.

3

Bleach water should be fine. You could leave out the ones with the graphics if you’re worried and let those soak for less time and rinse them sooner.

Also, if you have 10’s of thousands, I’d probably do this in a bathtub. Fill it up with water, dump in a gallon of bleach, let them all soak, stirring it around from time to time to make sure they fill with water, then drain it and start rinsing them. Make sure to get a hair thing to cover the drain so you don’t lose them.

4

Whenever I buy second hand Lego, I pick out the delicate parts for hand washing, then put the rest in a pillowcase, tie it with a zip tie and run it through the washing machine.