Any professional valeter worth their salt will tell you (and show you) that they prefer not
to use 'coloured' polishes. They have 'gear' that can mildly cut and 'move' colour already
on the panels so that it appears to fill them in when in fact it smoothes any edges so that
scratches don't show up anywhere near as much...in fact hardly at all. But for real damage
they obviously recommend a panel be sprayed.
The guy who did my silver Brabus at an open day had done my Star Blue ForFour previously,
and he used exactly the same 'gear' on both cars. No coloured polishes at all.
And he is real pro....he 'trades his profession' in London and does Ferrari's, Porsche's, Lambo's
etc etc. He will spend up to a day and a half on a single car...he even takes photos before and
after so that he can see what each panel was like before. It is also useful if he get's a 'dipstick'
who tries to blame him for any marks etc on the car....Some have tried !
Anyway, some of the gear he uses is phenominally expensive, and some he just uses one drop
of for an entire panel...it's that good and that expensive !
I also saw the results of his work on a ForTwo cabrio roof. He poured a 2lt bottle of water
over 2 roofs. One he had done, the other not. On the 'not done' it absorbed a lot of the water
and it was very wet to the touch. With the 'done' roof , the water 'slid' off, none was absorbed,
and it was bone dry to the touch immediately !