Grease. Paint. Oil. Carbon. Rust. Lubricants. Heat scale. Cutting Fluids. Ink. Yuck. Gunk. Whatever you call it, we refer to the stuff that needs to be cleaned as Soils.
At the chemistry level, Soils are either organic or inorganic. That should be the end if it in terms of how you remove them from surfaces. But it's not. Soils rarely behave the same way from one cleaning application to another, and your gunk is always different from the stuff being cleaned down the road. But knowing where to start is the first step to understanding your Soil. (And removing it!)
Here's a some examples of the Soils being successfully cleaned using Mirachem products.