We soak all moss and attached substrate in 10:1 bleach water. I spray it with natural brand Mite Off, after it dries we put it in a strainer and run exceedingly(near boiling) water over it. Put it in a moist gallon ziplock in the dark for 24 hrs. Moisten it with spring water then go. It also helps to put a good size bark piece under the moss. It gives it something to feed on/attach to. Makes the moss removeable once its attached without damaging it ;-)
We lurk all over the web. Dendroboard and monsterfishkeepers, with our local greenhouse taught us alot.