That's the question -- what do y'all use to wash moustache wax out at the end of the day?
I believe you use HairGum Barber Shop Wax. I've found Cremo Beard and face wash to work very well.
By the end of the day there is not much left, it seems to either get adsorbed or wears off, but I never worry about it.
Just wash normally, never had an issues with too much product remaining in my mustache.