no no i get it, just before letting her use your shower try something like “i’ve been trying to keep a routine going with my stuff, could you make sure to close the cap and rinse any soap down the drain when you’re done? it’ll help me a lot” this is a good way to not be accusatory (which stresses me out) but still gets your point across, and maybe makes her think she’s being helpful, rather than being accused of making a mess (even if she is, ppl don’t like to hear the truth a lot)