I have two 20# CO2 tanks and one 10# tank for sale that I picked up on CL a while back. In full disclosure, they definitely need to be hydrotested, are steel (not aluminum), are all empty, and one of the 20#'s has an old Coke sticker on it. I haven't had any problems exchanging them for new aluminum tanks but I've already got more CO2 than I need. Rather than have them sit in my basement, I'll sell them cheap. Make an offer, but I was thinking $20 each for 20# and $10 for the 10#. Local only, not willing to ship.