I did my lights with one of those kits at advance (someone opened it so they gave it to be for a buck) it has sand paper,polish, and some clear hard coating it helped some, but I did find all my cracks are on the inside of the capsule
I noticed this also with my old set the cracks and pitting on the inside of the lens out side cleaned up not to bad and you seen them but the inside was just way to bad.. was thinking of opening them up
and checking out things from there..