I have just bought a pair of 1-1/2" brass ball valves, which turn out to be inconveniently stiff to turn. I don't think they're faulty, just big, new and tight. I think lubricating them might help.
Products easily to hand are the water displacer that dare not speak its name and also SG85 spray-on white grease (see the bottom of
Any reason not to do this? I'm thinking of the seal material (PTFE?) being damaged by solvents or whatever.
Cheers,
Pete