You will need to take the headlight cover off, and reseal it so it is airtight. The current adhesive that holds the lens onto the housing needs to be heated up to make it pliable so you can manage to remove it. You do this by removing it from the car, then either putting it in an oven or using a heat gun and pulling off the lens. It isnt very difficult, but it does take time. If you arent comfortable with that, you will need to shell out some dough for brand new ones.