Clothing becomes filthy as it is worn, similar to food decay. Clothing that gets ‘too filthy’ will start to take damage and can’t be repaired until it is cleaned, eventually disintegrating. This is accelerated if the player is in sewage, slime, blood, bile, etc.
Clothing with non-cotton components requires special substances to clean rather than only soap and water - metal can be fairly simple, a scouring pad and a bunch of time. Leather and fur could both require complex but craftable solvents. Kevlar, neoprene, and nomex would all require cleaning materials that required a chemistry set, high cooking, and lots of time to craft, if they weren’t uncraftable. Something like a survivor wetsuit (cotton, kevlar, neoprene) would require soap, water, and two different chemical cleaners to clean properly.
