To prevent clogged spray tips try this after your next job: turn spray can upside down, then briefly spray to clear nozzle. You'll notice some initial pigment in the spray path, but it'll clear.
I have recharged cans of brake cleaner with compressed air, have not done paint.Yep. SOP, especially with spray adhesives but, unfortunately some paint/adhesive cans lose propellant (pressurization) when they sit on the shelf too long. I wonder if it's possible to 'recharge' them?
Also, in my experience, most paints, including Moss, work better with primer.