Hi Scott,
I started a thread about a Wormery I was given as a present
here . . .
There is concern about them causing blockages in the drainage, but generally a "tea" mixed from them could be seen as a good fertiliser.
It seems from the lack of replies in the original thread, not many Bonsaists have experience with using them, so best to keep it plain a simple to mixtures we know will work. But then, experimentation on a few lowly regarded pieces of stock might be an option.
Regards,
Ian.