There is a contradiction among some of the brands. InSinkErator’s disposal instruction manual states, “Don’t grind large amounts of egg shells or fibrous materials like corn husks, artichokes, etc, to avoid possible drain blockage.” Whirlpool’s disposal instruction manual states, “designed to dispose of food wastes including bones, fruit and vegetable wastes, pits, egg shells and coffee grounds.”
When rubber gaskets age, they can develop leaks. The gasket can dry up, crack, and leak when it is repeatedly exposed to long periods of disuse where no water is present in the drain pipe. Should an older garbage disposal be removed and then placed back, it will require a new rubber gasket to again achieve a watertight seal. Moreover, if a gasket is not evenly locked on all three sides, then it will develop a leak.