Pouring anything other than food scraps and water down the garbage disposal system can damage its blades and internal components. This includes items such as silverware, glass, metal, stones, or any hard object that can jam the motor and cause it to stop working.

Grease, oil, margarine, or lard should never be put into a garbage disposal system since they can solidify inside of the drain pipes causing clogs over time. After cooking with grease or fat, use paper towels to wipe up all residue before washing dishes in order to avoid issues later on down the road.

Coffee grounds are one of the most common causes of blockages in garbage disposals due to their sticky nature when wet, which makes them difficult for even water pressure to flush out completely from a sink's plumbing system resulting in build-up over time if poured regularly into it.

Stringy vegetables like celery stalks have an uncanny ability to clog up drains easily, so they should always be avoided by being poured into your disposal as much as possible. The same goes for potato peels, when not cut up small enough before being disposed of through it - this could potentially result in a major blockage requiring professional attention!