Definition
A brand name for a refined petroleum-based mineral spirits solvent used in aviation maintenance to clean parts, remove grease, oil, and other shop contaminants from metal components.
Plain English
A petroleum-based cleaning fluid that mechanics use to wash grease and oil off aircraft parts.
Context Anchor
Seen in aircraft maintenance instructions, cleaning procedures, and shop practices for metal parts or assemblies.
Derivation
Varsol is a registered trade name originally introduced by Esso (now ExxonMobil) in the 1920s. Like Kleenex or Velcro, the brand name became a common shop term for the product type — refined mineral spirits — even when a different brand is actually used.
Why Pilots Care
Mechanics need to know that Varsol is a specific class of solvent with defined cleaning properties and flammability characteristics. Using the wrong solvent on a part can damage seals, finishes, or sensitive surfaces, and improper handling creates a fire hazard in the shop.
Intuition Check
Varsol is not an aircraft fluid like fuel, oil, or hydraulic fluid. It is a cleaning solvent used during maintenance.
Example Sentence 1
The technician soaked the bearing in Varsol to remove the old grease before repacking it.
Example Sentence 2
After soaking the fasteners in Varsol overnight, the corrosion came off easily.