What type of groover do you have? If you've got the ecosafe system, any RV dump station will do. If you've just got ammo boxes it may be tough to find a place to clean them out as there are no scat machines in Colorado (that I know of). If you hear of a place that'll do plain old-fashioned ammo boxes, please post it - I've got a buddy with a Grand trip's worth sitting in his driveway....
Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse