Definition - What does Grime mean?
Grime refers to surface contaminants that commonly appear as dust/dirt mixed with oil, wax, etc. It is required to be removed from a material's substrate before applying coatings or paints, in order to avoid coating failures as well as to protect from corrosion.
Grime is very dangerous in electronics circuits, for example on monitor chassis boards, where high temperatures cause the outgassing of components coated with wax. This wax creates an enabling environment to form a sticky film on the board that traps dirt. The high-voltage potential of the monitor anode causes the monitor boards to be filthy and damaged.
Corrosionpedia explains Grime
Grime is a surface contaminant that causes coating defects or paint failures. Paint, by nature, bonds to the substrate. Paint needs a clean and stable substrate surface to adhere to. The presence of any dust, dirt or grime on the substrate surface results in compromising the ability of any surface coating to stick to the material's surface.
Metal parts are normally covered with surface contaminants like grime, oil and other impurities. This grime and oil can cause a metal coating to not adhere properly to a metal part, which results in the loss of consistency and quality of the metal coat. To avoid these contaminants, proper parts cleaning is essential to clear away all grime, dirt and chemicals that are present on the substrates.
Like a dirty surface, a glossy surface does not allow the new coating to grasp the surface. De-gloss all shiny surfaces by sanding or using a proper liquid de-glosser, along with removing dirt and grime.
Since grime usually consists of some form of oil or wax, it requires a detergent followed by mild scrubbing in order to remove the surface contaminants. It can be easily done through spraying the surface with a generous amount of a household, non-phosphate-based cleaner and rinsing. Grime can also be removed by wire-brushing.