Cleaning LEGO bricks? Stay at or below 40°C—and skip the dishwasher
LEGO recommends handwashing ordinary bricks in water no hotter than 40°C with a soft cloth or sponge. Treat electronic or metal-containing pieces separately with a damp cloth.
A dishwasher may seem convenient for a pile of bricks, but the official LEGO care guide warns that high heat, machine washing, hot-air drying and direct sunlight can deform pieces. First separate any electrical or metal-containing parts and handle small parts safely.