Buyers of used transformer oil typically include companies that specialize in oil recycling and re-refining, as well as industrial waste management firms. Some transformer manufacturers or maintenance companies may also purchase used oil for reconditioning or proper disposal. Additionally, certain industries that use oil for non-critical applications might purchase recycled transformer oil. However, due to environmental regulations, the sale and disposal of used transformer oil must comply with local laws and standards, especially if the oil contains contaminants like PCBs.

Different types of oil transformers include:

Power Transformers: Used in high-voltage transmission networks to step up or step down voltage levels. They are typically filled with insulating oil to ensure efficient cooling and insulation.
Distribution Transformers: These are used in distribution networks to deliver electricity at usable voltage levels to end-users. Oil-filled versions are common due to their reliability in various environmental conditions.
Instrument Transformers: Includes current transformers (CTs) and voltage transformers (VTs) that are oil-filled for accurate measurement and protection in high-voltage systems.
Autotransformers: A type of transformer with a single winding per phase that is partially oil-filled to handle high power levels with improved efficiency.
Hermetically Sealed Transformers: These are completely sealed units with oil, used to prevent the oil from coming into contact with the external environment, thereby reducing maintenance needs.
Pad-Mounted Transformers: Often used in urban areas or underground power distribution, these transformers are oil-filled and enclosed within a secure, tamper-resistant housing.