This is what freshly used CO2 cartridges look like on the inside. Some people believed that some oil was put into the cartridges to help the pellets on their way. Obviously they are/were wrong.

I just happened to slice one of the empties open for a look-see; and found more than I wanted. The rust is of a powdery consistency, and I’ll bet it makes a nice lapping compound in the barrel. I’ll look at another one from a different lot soon. Somewhere I read that Crosman CO2 has an oil in it to help lubricate parts. I don’t think so. These were made in Hungary. The container was just used up yesterday. Food for thought.

Update: I quickly expelled the gas from another cartridge (same lot), and it was rustier than the first one.