^^^ Yes, I agree. If you can't tell if they are yellowed out from the inside or outside, try the cheapest method first. Get some "Mothers Metal Polish" and buff it into the lenses really good. It will definently take some elbow grease, but it should be able to clear them up. Let the polish haze for a bit and then wipe off with a terry cloth towel. You should be able to see the yellow transferring over onto the towel.