Do not put makeup sponges, brushes, etc., in the microwave to wash, sterilize, or disinfect them.

Also, some people put makeup sponges or brushes in the microwave to wash, sterilize, or disinfect them... Although they may look fine on the outside, the plastic or sponge can melt, adversely affecting your skin and potentially releasing endocrine disruptors, so this is one of the beauty tips you absolutely MUST NOT follow!