Yeah, clay barring does work wonders.
I found that instead of the lube they sell , you can just clay bar while you wash....
I use a heavy concentration of zip-wax car wash soap.....and after I sponge the dirt off and rinse quickly, I go back over that section with the clay bar, keeping the surfcae all soaped up.
Works great on my factory finish vehicles...havent tried it yet on the fish (new paint).....but I figure it will work the same....
Just remember to wax it afterwards.