What Not To Compost & Why
Black walnut tree leaves or twigs- Releases substances that might be harmful to plants
Coal or charcoal ash- Might contain substances harmful to plants
Dairy products (e.g., butter, milk, sour cream, yogurt) and eggs*- Create odor problems and attract pests such as rodents and flies
Diseased or insect-ridden plants- Diseases or insects might survive and be transferred back to other plants
Fats, grease, lard, or oils*- Create odor problems and attract pests such as rodents and flies
Meat or fish bones and scraps*- Create odor problems and attract pests such as rodents and flies
Pet wastes (e.g., dog or cat feces, soiled cat litter)*- Might contain parasites, bacteria, germs, pathogens, and viruses harmful to humans
Yard trimmings treated with chemical pesticides- Might kill beneficial composting organisms