What I meant by my earlier post is that once you get the gun stripped and ready to take the valve out, sometimes they stick and are hard to get out. An airgun smith whose name escapes me now told me the trick of putting a cartridge in the handle and wrapping the gun in a heavy towel and then charge it. The valve will shoot out but will be in the towel. As far as lubrication a little Pellgun oil or non detergent motor oil is all you need. A drop or two on the new orings will suffice. You could use silicone grease too. You can oil the moving parts as well. I probably forgot something. You can get seal kits from Mac 1 airguns or Precision pellet. Mac 1 is in California Precision pellet is in Pa. I think.
Bob in WV
Never get in a hurry, it only slows you down.