I am having a kit with PMC for Christmas and I have read on here about using walnut shells for tumbling.
What I want to know is can one break up walnut shells them selves to use for that purpose. At the moment in UK we are getting walnuts from California. Quite expensive at 4.50 dollars per kilo. seems a shame to throw the shells away if I can use them. Can anyone tell me how fine I should break them down to. TIA