Several things you need:
A small bottle of paint thinner...
A thing of heavy duty and asorbent shop towels
A glass scraper "knife"
A 3m 320 grit sanding sponge (labeled for "sanding inbetween coats"
Pour some thinner on a towel rub it down a bit and pour some on the area to make it really wet.. Rub it harder...
Then go to town with the scraper.. The sh.t comes right off, but be careful not to cut yourself. Use the sanding sponge as needed on the area.. Keep doing that until you get it the way you like. Then tape things off as you like... Then sand down the whole lense just for a good measure, then respray.. Also rub some thinner on the clean lesr.. U may have to use a buffing wheel on the area or use some clearcoat spray to make the lense less clody,, ill post pics after work.