Thanks, Charlie. I do reuse pots because I have either clay pots or nice ceramic pots that I don't want to discard due to a lost plant. I had been putting them in a bathtub full of hot water and bleach (90/10 solution). Leave them in there for a few minutes and the bleach should kill anything that may be lingering on the pot. Don't do it in clothes you like very much, though.
I may try that with the worm castings and see what kind of results I get. I don't have any soil left and I need to pot up most of my plants so I ordered more. Hopefully no more will die on me too soon.