That store bought crap is nasty stuff for A/C machines, but usually a/c shops have scavenger machines that will evacuate a system if you did charge with the store bought stuff. The problem is sealer...that compound is what cloggs up the machine, I don't remember if it's the filter dryer in the machine, or the lines, but in any case, you gotta call a service technician (usually a MacTool, Robinair, or KentMoore rep) to go out and clean your machine, if it gets in there. Now a days, shops are supposed to, not saying all shops do this, they check for sealer first, before hooking up anything, then check the condition of the refrigerant if it's contaminated or not...THEN they can hook up the recovery, vaccum, and charge machines.