The story
Trade name. The company states that it derives from swarf, an old Derbyshire engineering term for oil and grease, and a variation of eager, i.e. eager to clean.
Etymology from Wiktionary, CC BY-SA 4.0.
Swarfega
Today it means: A heavy-duty gelatinous, thixotropic substance used to clean grease and oil, etc. from the skin. Full definition →