Brother in law was a pro car valet and he did a smashing job. He always swore at Autoglym.
Do note that all the car products that have 'polish' in their name are abrasive and sooner or later will wear off your top protective clear coat from the paint.
I've used a number of specialised polishes on rotary and dual-action machines and the best I've come across for removing minor surface scratches (or restoring after clay bar) is Britemax Black Max Ultra Fine, which can and will remove 4000 grit marks. Do note that although it is ultra-fine it is also rather fast cutting, do not get carried away with it. The AG and Megs polishes contain silicones and resins which Black Max does not, so you can spray straight down on it if required, or apply a pro paint sealant.
Then seal the fresh surface e.g. Britemax Extreme Elements, then wash and wax it. The carnauba car waxes set almost as hard as concrete and protect the paint through winter and several washes.
Having got a motor tarted up I lose interest and run it through an automatic car wash when I get a tuit.
Edited by: jefrs