Rat grease is a colloquial term used to describe a type of low-quality or adulterated butter or margarine. It is typically made from a mixture of animal fats, vegetable oils, and other ingredients, and often contains artificial colors and flavors. Rat grease is generally considered to be an inferior product, and is often used in cooking or baking when cost is a primary concern.
The term “rat grease” is thought to have originated in the United States in the early 1900s, and was originally used to describe a type of butter that was made from the fat of rats. This type of butter was often sold to unsuspecting consumers as a genuine dairy product, and was often used in cooking and baking. Over time, the term “rat grease” came to be used more generally to describe any type of low-quality or adulterated butter or margarine.