Whenever I swap or stop using any of my barrels/liners I always clean them thoroughly first before storing.
I have this my selection (based on different twist rates) collected over several years, each barrel and liner has its own function depend what game I wanna play next.
Today was one of those grey days, what else to do...let me do a quick maintenance on my inventory.
Cleaned the bore with Ballistol (in the garage of course), dry them with couple of clean patches, and re-lubed with soaked PTFE oil.
But I noticed for first time something new to me, a light surface rust even if the material is Stainless. No problem, a light touch with steel wool did the magic, but I would like to put some coating now, these will be sitting at least the next half a year until next year season.
What you friends use? that is indoors (odourless) friendly