So long, WD-40! It's been fun, but I've had it with you! (small rant)
Tell me more, tell me more!
Oh boy, I figured that was coming :)
A big factor is I have a homemade air gun, a simple small ball valve reduced down and a 3/16 brake line silver soldered to it with the flair outwards.
figure out how to tear down a dead bic lighter, you want the little brass valve that`s in it. chuck the longer part in a drill press and touch a file to the ball end to get it a little smaller until it slips into the can tube you want to recharge. Set the compressor regulator to no more that 90 lbs. yeah that much, scary I know. put your version of a blow gun that will slip over that Bic valve, wrap a rag around it just in case, and open air gun a push down on can valve, listen to it equalize then retract.
Bam... you now have a recharged can so you can use the rest of the product.
If you want to go through all that ****, it does work.