Final answer:
Effective cleaners for grease and oil on metal surfaces include surfactants, alkaline salts, enzymes for protein removal, chelating agents for rust, special complexants for silver, and acidic agents for scaling.
Step-by-step explanation:
When attacking and dissolving grease and oil on metal surfaces, several classes of chemical agents are highly effective. These include:
Surfactants: Especially fatty alcohol or alkylphenol polyglycol ethers, which have the ability to lower the surface tension of water, emulsifying oils and preventing spotting on drying.
Alkaline salts: Such as metasilicates, alkali metal hydroxides, and sodium carbonate, which can dissolve grease but are dangerous if ingested.
Enzymes: These are used to break up protein-based and possibly oil and fat deposits.
Chelating agents: For ferrous metals, citric and phosphoric acids are common, these aid in tackling rust without being aggressive.
Silver requires special complexants such as thiourea to remove tarnish. For stainless steel and other nonferrous metals, lactic, citric, or phosphoric acid based cleaners with added solvents are often used. Acidic cleaning agents, which primarily involve strong mineral acids, are typically used for the removal of inorganic deposits like scaling, and they often contain surfactants and corrosion inhibitors to mitigate the harsh effects of the acids.
In summary, the effectiveness of a cleaner for metal surfaces depends on its ability to deal with specific types of dirt and residue, with a variety of ingredients contributing to this capability.