Car Polish is covered, I use a brand from Asda and I have contacted the supplier and he has given me some information with regarding to safety etc..
As far as Insurance policy, I have checked with my insurers and it's ok!!
It reaaly does save time for the regular cleans, especially in our hard water areas. Limesacale doesn't stick and just a quick wipe over it really does give a high shine.
You need to replace the polish every six weeks or so.
We use it, our clients really love it,better than anything else.