Welcome to the club! Servants of the school. At least our janitors have sinks and 3 rooms to work in. I have neither I really sympathize with the paint. I'm covered with it too at the moment. Our sink is a pail in the room and I spent lunch cleaning the pallettes dummy me I could have used paper plates and pitched them but I hate to waste.
I paint once a semester so that's it. Bye bye. THe HS teacher hardly ever paints and everyone goes gahhh gahhhh over her displays. THey use colored pencils and she takes weeks with one project. I couldn't get MS kids to do that but it is admirable. My kids have a variety of experiences but I really am burning out.
Get super organized, use squeeze bottles for paints, paper plates. Make them do the work.
Hang in there IT's payday and someone probably appreciates us somewhere ????\