Best lube for grey tank and black tank valves

Grit dog wrote:

Bobbo wrote:

MitchF150 wrote:
How would you "lube" them in the first place??

Dump the tanks, close the dump valves, dump in a quart of vegetable oil, open and close the dump valves rapidly a few times to spread it around

^Are you serious?

yep, IIRC that was the directions on the bottle of lubricant that I bought years ago. drain tanks, put in lubricant so it will settle down to low spots in system drain.
bumpy