Removing the Headlight Lens
If the lens is broken/cracked, remove it as described in Removing A Broken/Cracked Headlamp Lens
Heat the lens at the adhesive in the headlight housing using high heat so that the lens becomes really warm.
Insert the knife between the lens and the plastic edge. Carefully pull the knife through the adhesive around the entire housing a few times while heating the top of the lens (be careful not to damage the plastic edge with the knife).
Bend the lens straight up about 5 cm starting on the side at the outer end.
Raise the lens and hold it up. Use the knife to remove the adhesive from the inside and remove it from the interior of the headlight housing a little at a time so that no adhesive residue ends up on the black decor panel when the lens is lifted straight up from the headlight housing.
Remove any adhesive residue from the black decor panel on the inside of the headlight housing.
HINT: H Cleaner, 1161436