I took a hiatus from kegging because I wanted to dedicate my chest freezer to controlled fermentation, and focus on bottling and honing my brewcraft.
Now I'm returning to kegging, and I have an aluminum CO2 tank last filled two years ago. (Got it from an exchange system, lucky that it's in such great shape -- I plan on certifying and refilling it from now on)
I know aluminum is non-corrosive, but can the liquid CO2 go 'stale' in this container? Are there any safety risks with suddenly using it again?
I ask, because I plan to rack a beer into a keg in a week or two, and am not interested in ruining it with bad CO2. I do plan on cleaning and sanitizing all my QD, and replacing vinyl lines.
Second question: is it necessary to clean/sanitize anything else?