I've been thinking about this for a long time - a good many people mention throwing their scrap in the back yard. Please be aware that runoff from clay, when it enters any waterway or storm drain, would be a pollutant. Not because of toxic materials, but because of the turbidity it causes. So, if your yard drains to any waterway without treatment (like a stormwater pond), please don't. At certain times of the year, the turbidity impedes the development of some of the critters that keep our streams healthy. Likewise, if it ends up in a bay, it's a bad thing.