Getting my gear set up to start kegging and a friend gave me an old cylinder. Nice big steel one. Problem is he does not remember for sure if it was for co2 or for nitrogen. He is fairly sure it was his nitrogen tank. How can I tell them apart since there are no tags or stickers on the cylinder?
Second question. I looked at the stamps on the cylinder and the last one was from 1988. Looks like its been sitting in the garage for a long time. Is this tank still any good? Or should I just take it into Airgas and see if they will exchange it?