I'll probably take a bunch of crap for this but whatever. Either here or at work I use stuff from outside ALL the time. Rocks, logs, sticks, moss, leaves, mud, you name it. How much of it have I sterilized beyond picking off obvious insects or clumps of dirt? Not very much. I've yet to have an explosion of nesting beetles, wasps, lice, mites, rodents, or anthrax come out of "dirty" nature. Maybe it'll come back and bite me someday, but I'm not going to be paranoid. Personally I think if I had to boil or bake everything I put on vivs for either snakes or frogs or whatever, most of it would be dead (moss) or burned.