1.VerbTo rinse (something) completely from top to bottom.
"Best practice in washing your car is that you should rinse it down before beginning to wipe or scrub with the soapy sponge, as you'll reduce the degree of abrading the paint with fine dirt particles."
2.VerbTo send (something) down the drain by rinsing action.
"There was some food residue in the sink, so she rinsed it down."