this may be a dumb question. do i have buy a new gasket for my valve cover when i want to take them off to polish? Second gasket question. I noticed that the spark plugs show signs of exhaust leak. I was going to take them off and touch them up with paint and reinstall. I would assume I need to buy a new gasket to reinstall. Are there any tricks so that I can ensure I get a good seal? I don't know if I need to use some sort of liquid gasket stuff along with the regular gasket.