What really is in a car polish?
The main difference between a polish and a wax is essentially polishes contain abrasives and waxes do not.
You use a polish to rub onto your car to essentially make the finish smoother. Polishes can contain a lot of abrasive to a little abrasive.
Polishes containing a larger amounts of abrasive are used to remove heavy oxidation and flaking. On the opposite scale, a polish containing barely any abrasive at all is there to remove a very light layer of dead paint skin and then shine the paintwork and make it is as smooth as possible.
Polishes, in real terms, contain no protection; it simply just makes the surface of the paintwork smoother. However there is an overlap to this as some sealants on the market also contain a small amount of abrasive and are there semi classified as a car polish. So, it can be quite confusing as there are overlaps between the chemical car polish formulations.
If your car has been neglected, it is a very good idea to use an abrasive polish just to get off all that dead skin. This will certainly boost the shine as well. Then, it is definitely a great idea to use a protection product on top, whether this is a wax or a sealant.