Coffee Grounds - Although grounds appear finely milled, they are dense and turn paste-like when removed from the filter. This is a surefire way to clog your drain.
Pasta, Rice, and Bread - These foods all absorb water and expand, making them easy culprits for drain clog.
Animal Bones - Bones are too difficult and tough to grind.
Nuts and Shells - Your grinder is simply not built for this type of food.
Pits and Seeds - They are small and hard, not ideal for disposal. Rule of Thumb: If you can’t cut it with a knife, throw it in the trash.
Egg Shells - Their membranes can obstruct the grinder.
Stringy Fruits and Vegetables - The fibrous strands may be good for your health but they are bad for your grinder, especially banana peels, celery, corn husks, or rhubarb.
Potato Peels - Potato peels can catch in the drain. Avoid starchy beans and vegetables as well.
Grease, Oil, and Fat - These can congeal in your pipes, causing a blockage.
Non-Food Materials - This should be obvious. If it isn’t biodegradable food, it should not be thrown down your drain. Paper towels, plastic wrappers, tissues all can lead to major plumbing problems.