Just get some 1000, 1500 or 2000 grit wet n dry sand paper. Wet sand headlight then buff with buffer at around 2000 rpm with Meguiars # 9 power clean.
I saw on the first post clearcoat came with one of the headlight kits. According to a painter at a collision center I worked he said buffing lights without spaying them with clearcoat defeats the purpose.
I never cleared mine after a buff on my 98 Catera ( of course that was just to get it ready to sell for my SHO), but my 97SHO well may be worth pulling them out after buffing and spraying a coat of urethane clear.