Effective cleaning is based on the principle “Equal dissolves equal”. To achieve optimal metal cleaning results, the cleaning agent should be chemically similar to the contaminant.
There are polar (inorganic) and non-polar (organic) contaminations. For water-based (polar) types of contaminations such as coolant and lubricant emulsions as well as solids like chips, salt, residues of polishing pastes and particles, aqueous cleaners are typically the first choice.
These are available in neutral pH, alkaline and acidic formulations, and a huge variety of surfactants and other ingredients.
When removing mineral oil based, non-polar contaminations, such as machining oils, greases and waxes, solvent will commonly be the preferred cleaning agent.
Nowadays modified alcohols are also available; due to their both non-polar and polar properties, they are able to clean non-polar contaminations as well as certain polar contaminations. This type of solvents has a much broader application range compared to traditional non-polar solvents.