Boshuko is a powder mined in Japan that is used to polish enamel
pieces. It can be purchased through Enamelworks Supply Co. in
Seattle at (800) 596-3257 and I must add that Coral is really
knowledgable and helpful, as has been mentioned before by orchids.
To quote Coral Boshuko “can be used much like pumice or cerium
oxide to prepare an enameled surface for buffing, to help remove
pickle residue or to be the final polishing stage for a 'ground’
finished enamel” It comes with an instruction sheet from
Enamelworks on its usage. My experience finds that it’s kind of
messy, but fun to use if I am in the mood and the finish is pretty,
like a polished river pebble. It feels great to the touch.