Yeah, dirty clothes could be a cool mechanic, have it add a flat debuff to the hygiene modifier or something; an incentive to actually interact with the washing machine even if you are inclined to avoid situations that gets your clothes dirty.
Having dirty clothes already reduces your hygiene stat. That mechanic is already in the game.
Do you mean ones that are stained? If so, I just mean from grime from daily use.
Exactly, that's what I meant, too. A different "class" of dirty.