Comment by giantg2
"Sane folks just use supplied air anyway, rather than risk it at all."
For small one-time projects it's generally fine to just use a brand new filter and toss it afterwards. Hobbyists painting a car panel aren't using supplied air.
Sure, i meant if you are doing work repeatedly.
People often put the cartridges in a plastic (or sometimes mylar if they are advanced) bag to save money, and change them when they can smell stuff. This is a bad plan with isocyanate.
Auto finishes are moving towards iso-free 2k urethanes anyway. (wood will get there, but tends to lag)