Spray the lubricant onto the valve where the valve handle enters the actual valve body and let it sit for about 20 minutes. Then, try loosening the valve by hand again. If it doesn't move, or is still difficult to turn, tap it lightly with the hammer.Mar 5, 2020
Can a water shut-off valve go bad?
You can spend time rebuilding the old valve, but the problems will just reappear years from now. The best way to deal with bad valves is to replace them with modern quarter-turn ball valves. They rarely lock up, leak or wear out and best of all, they'll take just an hour or so to install.
How do you remove a corroded water valve?
https://www.youtube.com/watch?v=16JiUUzJ2tg
How do you free a jammed stopcock that won't turn?