Which surface contaminant cannot be removed by cleaning parts in a vapor degreaser?

Which surface contaminant cannot be removed by cleaning parts in a vapor degreaser?

• A. rust
• B. oil
• C. grease
• D. scale

Answer: (A)

Vapor degreasing relies on the solvent to dissolve organic soils like oils and greases that are soluble in the cleaning solvent. Rust, on the other hand, is iron oxide—a corrosion product that forms a hard, inorganic layer on the surface. The degreasing solvent doesn’t dissolve metal oxides, so rust remains attached or only flaked off as loose debris. Oils and greases are removed because they are soluble in the solvent, and scale (a mineral deposit) often requires different treatments beyond vapor degreasing. So rust cannot be removed by cleaning parts in a vapor degreaser.

Vapor degreasing relies on the solvent to dissolve organic soils like oils and greases that are soluble in the cleaning solvent. Rust, on the other hand, is iron oxide—a corrosion product that forms a hard, inorganic layer on the surface. The degreasing solvent doesn’t dissolve metal oxides, so rust remains attached or only flaked off as loose debris. Oils and greases are removed because they are soluble in the solvent, and scale (a mineral deposit) often requires different treatments beyond vapor degreasing. So rust cannot be removed by cleaning parts in a vapor degreaser.