Never put grease, hard food items, fibrous materials, non-food items, or contaminated food into a garbage disposal.

More Info: Many have the misconception that you can send anything food related down the disposal. The notion that it will grind up anything and everything and wash it away is incorrect. Most garbage disposal systems are designed to grind up soft foods. Putting improper materials into the garbage disposal could clog pipes and/or ruin your appliance.

Disposers vary in grinding power so the following are general guidelines of materials best disposed of by other methods:

Grease, oil, and fats: As a liquid, grease, oil, and fats go down the drain easily. Once they congeal, they build up in the sewer pipes that carry wastewater away from the home.

Fibrous food materials: Celery, cornhusks, and artichokes are examples of foods that should be avoided.

Hard food materials: Most disposals have a tough time with food items such as bones, fruit pits, and seeds like popcorn kernels.

Eggshells: Large amounts of eggshells ground at once have the potential to collect in pipes

Non-food items: Disposers are designed for soft foods. Items like plastics, metal, paper, and glass have the potential to ruin you disposer and do not belong in the wastewater.

Contaminated food: To prevent foodborne illness outbreaks, the CDC advises not to put food suspected to be contaminated down the garbage disposal.  The CDC makes the following recommendation: "Dispose of food that may be contaminated by placing in a sealable bag, wrapping another plastic bag around the sealable bag, and then taping tightly. Place bags in a trash receptacle for non-recyclable trash outside the home and out of reach of humans and pets."