make sure everything is air tight, when i did my diy black housing headlights, i sealed everything over 3 times, remove your head light assemblies and check for open seam, fill it and while youre at it check the bulb sockets for cracks and openings, if theres anything like it just make your own o-ring on the bulb sockets with some silicone. afterwards grab one of your relatives hottest hair blower such as a 1785 or 1885 watt dryer and heat up any bonding material on the lenses squease those f**kers tight, careful not not to break em.