I've used a couple of different techniques to "improve" the looks of chromed headlights on older kits and/or promos... I've painted a light coating of off-white acrylic paint over the chrome headlight lens and after that dries I apply a light coat of either clear enamel, Elmer's Clear School Glue, or, clear epoxy to give it a clear shine. I've also used clear enamel to glue spare, clear headlight lenses in the right size from my parts stash over the chrome lenses.