It isn’t wasting beans to season a grinder if you source them properly. Roasters will use have many kilos lying around from failed roasts, profile development, or cupping, not to mention coffee that may be way past its best. All coffee they’d otherwise throw away at a loss. Offering to cover some of the cost can help them as a business and by extension help the farmers. Now whether or not it’s a waste of your money, your time, and your electricity….