I was thinking I'd hand wash it with warm water and then let it hang dry.
Edit (of course): 2. Is it rude to sweat on someone's car seat? My coach gave me a ride home after the tournament. His car has leather seats, and I was wearing shorts and it was hot inside the car so my legs were sweating on the seat. I tried to discreetly wipe it with my hand but when I got out there were some damp marks on the seat (not like gallons of sweat and not malodorous). In the future, should I sit on a towel?