Yellow grease

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Yellow grease is a term from the rendering industry. It usually means used frying oils from deep fryers and restaurants' grease traps. It can also refer to lower-quality grades of tallow from rendering plants.

Yellow grease is recovered, traded as a marginally valuable commodity, and has traditionally been used to spray on roads as dust control, or as animal feed additive. But waste restaurant grease has recently become more desirable as one source of biodiesel fuel for cars. Although most biodiesel is developed from renewable plant sources, especially soybeans, yellow grease is attractive because it's cheap, it turns waste into fuel, and the exhaust purportedly smells like french fries^{[citation needed]}.

"SVO" (straight vegetable oil) refers to any unused vegetable oil that can be used as an alternative to diesel fuel but which has not been chemically altered and made into biodiesel. "WVO" (waste vegetable oil) refers to yellow grease also used as an alternative to diesel fuel but which has usually been mechanically cleaned (filtered and de-watered), but not chemically modified into biodiesel. Confusingly, yellow grease is a WVO but can be assumed to contain beef tallow, chicken fat, and other animal products.