All you need to do is soak the pots in a bleach solution for a few minutes and then rinse them for a few minutes. The bleach is a 12% solution and is readily rinsed out of the clay just as quickly as it went in. Virus and all the other critters we are skeered of are oxidized instantly by the sodium hypochlorite in the bleach. The chlorine gas is not available as gas in a bleach solution.