In the world of polishes there are several grades. Among them are the compounds. These are the rough polishes aimed at more cut and less refinement. A compound is often used in combination with a rotary, but can also be used with a polisher.
When to use a compound
When you have surface imperfections that need to be polished out, some imperfections might be to deep to polish out with just a medium polish. For these deeper scratches ou can use a compound. These are aimed at much more cut, with less finish. This means that this steps always needs to be followed up by a finer polish. A compound is often used for very deep scratches or to polish an area that has been wetsanded.
Not every manufacturer calls the polish with the highest cut a compound, these can also be referred to as a polish with high cut. Some brands might even come up with a specific name for the range with very high cut. Besides the very subtle name differences, there isn’t a difference between these polishes, although the highest cut from a certain manufacturer might not cut as much as the highest cut from another brand.