When cleaning the next batch put a cup in a container and add a cup of water work the beans with your hand and watch how much dirt ends up suspended in the water.Then repeat this procces until the water remains clean.I use the same tech. with my wheat n barley as well which are not sprouting grade.You can buy bulk sprouting seed at wheatgra SSKI ts.com and the handypantry.com I get mine in 35lbs. buckets.Good luck and happy sprouting.Jeff.