I've used one of these canisters in my old Jag. You pull the pin on the f**k*r, sit it in one of the rear footwells and then as you say, let it recycle for 20 mins and bang! Bob's your mother's brother.
They are perfect for getting rid of bad bacteria and musty smells. And at £7-10 a pop it's hardly ball breaking financially.
They won't however, in any way, improve the performance of the a/c. As others on the thread have mentioned, the once yearly, regas and service of your a/c is what's required to keep things cool
...... But even the regas/service won't always clean up smelly a/c systems though.
Best off using both methods i.m.o
