The secret to keeping free moving seacocks is to exercise them. Grease is good, but move them regularly and they move easily. Our Helmsman has metal (bronze I hope) seacocks. We keep all seacocks closed unless the system is in use. 11 years now and so far no lubrication needed. We were surveyed recently the surveyor had never come to survey a boat and found all seacocks closed. >From Forespar: QUICK NOTE ON MAINTENANCE New valves come greased. Valves that have been sitting on store shelves for a long time may need more and have the handle/ball exercised. Use any non-petroleum grease (Lithium, Silicones, etc) and no aerosols! Use a soda straw to get the grease through elbows and tailpipes and USE THE VALVES regularly to avoid marine growth from building up and seizing them. The more you use them the less you have to maintain them! Cheers, Tom 410.212.7898