I want to have a CO2 FE on hand as well as the dry chemical FEs I now have in the house and garage. The dry chemical FEs are easy to source at the home center, WalMart, Costco, etc. but I have not come up with many options for sourcing CO2 FEs. They are recommended for nuisance fires, since they don't leave any residue and can be used multiple times before refilling. I'd also like to locate a place to get it refilled. Any wisdom to impart?