What is waste oil?

Waste oil refers to oil that has undergone significant changes from its original refined state due to usage, exposure to contaminants, or degradation over time. This alteration renders it unsuitable for further use in its current condition. When oil is used in engines or other machinery, it accumulates impurities such as dirt, metal particles, and combustion byproducts, which can adversely affect its performance and safety. Therefore, waste oil is considered to have lost its utility as a lubricant or fuel in its original form and must often be disposed of or processed before any potential recycling or re-refining can take place.

In contrast, the other options describe oils that may still hold value or can be reused without significant modification, which does not align with the definition of waste oil.