From what I've seen, clay bar is only for deposits in the paint. Do a thorough wash, and feel the paint. Theres a trick detailers use, being a plastic wrapper or baggie.

It will blow your mind. Rubbing it with your bare hand, the paint feels nice and smooth, rub it with the plastic, and you'll feel what seems like sandpaper.. Same finish, but the plastic amplifies whats there.

The detailers I know (my brother owns a detail shop) use a spray bottle of water or even glass cleaner while they clay bar the surface. Then, of course you need to high speed buff the paint. (an orbital is NOT high speed)

A black/dark vehicle can take 3-4 steps, easy. Being clay bar, then buff with a mild cutter, then polish, and then a sealer. Even then swirls can show up. Wax will only "fill in" the swirls. That's why they come back after a few washes.

That's why my X is silver...Lol