Looking to remove the plastic lenses from my headlights and give them a total refurb...what is the best way to remove the lenses and when replaceing do I need to apply more sealer ,and if so what is the best stuff.

I used 2 blunt screwdrivers to gently prise the lense of and cut the sealant with a knife as I went. The sealant stays "wet" and mine re-sealed without any extra sealant and have stayed dry. I am sure someone will tell you what the sealant is so you can do a better job, but mine are fine.
Al