To ward off pests, vermin, potential garden infestations, and disease, avoid organic materials that could cause problems during or after composting including:
Cat or dog fecal matter
Dairy products
Diseased or insect-ridden plants
Fat
Fish
Grease
Lime
Meat
Oil
Unwashed egg shells
Weeds that are hard to kill (i.e., bindweed and quackgrass)