We preserved a wood cookie from a little white oak using Epsom salt. Plastic Tupperware tub big enough to accommodate the piece, fill with water until piece covered 1/2 inch or so, take out piece and add Epsom salt until no more will dissolve (super saturated ?) put piece back in. We had to add a stone to hold it down underwater. Set it some place out of the way and let all the water evaporate. It finished off nice with just some sand paper. Its over a year old and has not checked, and is still holding the bark.

Bob