Drug info - Effective ways of powdering dry truffles?

[honourableone]

SWIM has spent a long time looking for information here, and hasn't quite sated his curiosity. There is a method involving placing mushrooms in a freexer bag, covering with a magazine, then hitting them repeatedly with a shoe, but SWIM doubts that this would work with truffles. There has been mention of using a coffee grinder, but SWIM doesn't have one and doesn't know whether this could cause any of the truffle powder to be lost or difficult to get (which is one of the main issues in regard to this thread).

What other methods would work well and ensure that all truffle residue was easy to get? Would a mortar and pestle (which might be a good investment anyway) work, or would the truffles just ping around without getting crushed?

Thanks