Hi Chris Leeson @chrisleeson
Yes I use a clay on my cars, almost normal practice these days. Lots clays available – I use a Bilt Hamber medium (from Amazon) as suits UK climate. (softer than some) Normally only use in summer months when doing a proper clean.

You should try it, as quite a revelation, leaves the paint so smooth. I wouldn’t have believed how many small particles it removes. Just use with plain water or ideally water and car shampoo mix as a soapy lube, work on one panel at a time. I don’t use any of the special fluids they sell..
You can feel the difference with your hand once done. Strange process but IMHO it works.
Won’t restore indifferent paint but definitely makes good paint even better.

I also use snow foam when car has got bit grimy prior to washing off. I’m less convinced about the foam but does allow a hands off first wash..

Regards, Robin