NOT Dumping Black and Gray Tanks

[SkiSmuggs]

While folks seem concerned by the solids, it is the urine that makes the stink. Solids have the bacteria from your body to help break it down. There are compost toilets on some hiking trails here in Vermont with signs asking that you pee in the woods so as to not disturb the composting process.
FWIW, we have had our RV sit over a winter with stuff in the black tank and it's always been fine to wait until we are at a campground again.