While traveling in the USA, rest stops can be convenience stores that sell food, fast food places, and grocery stores, all required to have restrooms.

Wherever I stop, if the facilities are clean, I always leave a tip "for whoever cleaned the restroom last" at the front counter. $2 to $5, depending what change I have and how clean it was.

Sometimes they decline it. Usually if the owner is at the counter, they decline it with thanks, otherwise I think they appreciate an actual token to go with the "good job".

The old lady at the French 'toilette' would get the same if it were clean, or none if it were not. If she complained, I can tell fortunes as well as she can ....!

Lannis