I might add that it is even worse to suck refrigerant with magic sealant into one of my recovery machines. If you want to protect them these days you have to be working on KNOWN systems or use BOTH a refrigerant identifier AND a sealant detector. As far as I'm concerned, they can make it illegal to sell the magic A/C sealing products and it will be fine with me, and that is coming from someone who is very much against big government.