You could also use Crosman Co2 cartridges which have Pellgun oil in them.

I tend to buy 100 CO2s at a time online and go for the cheapest option - they can sometimes be Crosman believe it or not. If using others then a drop of Pellgun oil every third cartridge will keep things sweet.

TBH - I have quite a few CO2 pistols and only had one seal fail over the last few years (and that was on a 50 year old Crosman 600 on it's original seals) and this is regardless of whether they are stored with or without a charged cartridge installed.