Make a “water sandwich” by turning on the water for a few seconds, then activate the disposal, run the water for at least ten seconds after turning off the appliance. This will help ensure all waste makes it to the street.
Avoid stringy and fibrous matter, especially celery, corn silk, and like foods. It’s not a garbage can so filtered cigarettes qualify as forbidden items as well. Don’t laugh, we’ve had to remedy this.
Here are some quotes from other plumber friends:
Stringy or fibrous foods
“Beware of stringy or fibrous matter such as corn shucks, corn silks, celery, etc. Bones are a no no. You should have a minimum of half-horsepower disposal and stainless steel blades. Always run water when using the disposal.”
Carrots and potatoes
“We’ve seen bad things happen with carrot greens, potato peels and the like. But the worst was white rice, because it travels easily down the pipe a way then hardens into a gelatinous mass, which necessitates cutting the pipe out.”
“Grease is the worst thing to put down any drain. Also, any type of stringy vegetable like celery or banana peels should be avoided.”