Since you can't use oil based products on Acetylene torches, what is the best way to keep torches and tips clean?

Tips are cleaned with little kits that contain a file and some little toothy wire rods. You simply burnish the end of the tip with the file and push the appropriate size wire rod down the hole or holes in the tip.

Do not use any thread sealer. Just keep everything clean and completely free of oil or grease. Typically, the torch head to torch body connections are hand tight only. The torch to hose body connections are wrench tight but not incredibly so. Barely tight enough to not leak is what you want.If your threads are dirty use a tooth brush or something with soft bristles. Brass is soft.