[C320-list] Sink drainage?

[Dave Hupe]

 I have been regularly greasing my thru-hull valves from below with a small stiff brush when the boat is on the hard, but don't feel that the entire ball gets lubricated that way …. and I'm not going to pull hoses off the valves from inside.  Moreover, you couldn't do that effectively if there is a 90 degree tail coming off the thru-hull. Though I have not personally used it, Marelube liquid https://www.forespar.com/products/liquid-marelube.shtml  sounds like an ideal way to lubricate valves for things like the galley and head sink drains, where you can pour it in from above, have someone hold a pail below to catch the drainage as ypou work the valve, and then you can reuse the drainage to repeat it in the same drain, or use the drainage in another drain (economy here). 
Dave Hupe (#32)