Oyster Shell on the Farm
Oyster shell is normally fed to chickens to strengthen the shell walls of the eggs. Laying hens need a source of calcium to keep their eggshells strong. Hens that get too little calcium will lay thin-shelled eggs that will be prone to breakage. Eggshells are made of calcium carbonate, the same material as found in oyster shells.
So, oyster shell can be purchased anywhere chicken feed is purchased. Farm stores (Farm & Fleet and Fleet Farm stores in the midwest), feed mills, and other locations of this type. It is generally sold in small bags, but don't hurt yourself. These small bags are heavy. Usually 50 or 60 pounds.
Oyster Shell for Corn Burning
The calcium carbonate reduces the starch/klinker build up in the firepot and makes the klinker much softer. A little bit goes a long way. The most you should need for a full season of heating a normal sized home is one or two bags.
Due to the possible wear of the auger and loss of warranty, many have been placing a small hand-full of Oyster Shell directly in the burn pot instead of the fuel bin. There are other substitutes for Oyster Shell which may not be as harmful to the wear of the auger:
Also see: AES Clean Burn Additive