Putting certain foods and items down your garbage disposal can cause damages to the blades and lead to smelly, unsanitary clogs. Avoid putting bone fragments, eggshells, coffee grounds, fats, oils, onion skins, banana peels, pasta, potato skins, unpopped popcorn kernels, fruit pits and seeds, corn husks, and stringy vegetables like celery or asparagus down your garbage disposal for the best results.