If you really want cheap additive go (sorry fat fingers) with diatomaceous earth. Probably 20$ for a 50# bag of food quality. Shipping on the other hand.
But seriously diatomaceous earth is a mild abrasive used in some things like polish and tooth paste. Organic food or organic garden sources will have small bags for not too much for a lifetime supply even though the price compared to commercial market is amusing.
But seriously diatomaceous earth is a mild abrasive used in some things like polish and tooth paste. Organic food or organic garden sources will have small bags for not too much for a lifetime supply even though the price compared to commercial market is amusing.