Washing my hair while teardrop camping last weekend.
If we're not camping near a shower, I'll sometimes wash up in our dish pans. It seems gross, but I'm fastidious about washing out our pans after washing dishes and body parts. We use these versatile little containers to not only wash dishes, clothes and hair, but to hold dish cloths, pans and our garbage bags in the back of the galley.
If you are going to wash your hair in a dish pan while camping, it does help to have shorter hair.