It's common,there's not much you can do to prevent it and mfgrs certainly don't want to because it make's them money. The problem started when EPA regulations forbid releasing most refrigerants. Mfgrs briefly used propane which worked well albeit not as well as earlier refrigerants. Liability and lawyers ended the pratice of using propane so they began using refrigerants which weren't banned for release. Current Rs don't have near the pressure curve as earlier Rs or propane. If the contents are used at 80f,you can pretty much use the intire contents "IF" a liitle is used,can alowed to warm back to 80f and a bit more used until it's all gone. If sprayed at 50f,twice as much propellant is used compared to 80f. I'm not going to teach a 101 course on the subject so if you want to better understand,google "temperature pressure chart". Re-pressurizing can with air hose is short lived and must be done over and over. If you are going to mess with re-pressurizing,use propane or freon. Handy-Dandy Tips,cool spray can in freezer and turn nurse tank upside down while charging so that liquid flow's and the whole can will spray without recharging and like the old days can will still spew after all the contents are gone.
I toss paint in trash, poke a hole in lubricant cans and pour them in a gallon jug with transmission fluid and diesel laced with acetone.
