Get some specalist glue remover, you can use household stuff but its not as good. I like autobrite stuff or even dodo juice tar and glue remover. Tardis is supposed to be exelent
As for the paint, as stated above but use a decent paint cleaner or machine polish it with a da or rotary with the right polishes, for quicker and better results.
For keeping the finish protect with a couple layers of decent wax. Collinte is a good cheap long lasting wax. My current favs are bouncers or definative wax but are more pricey