"Alpiners'.....As you read through the posts, I'm sure you'll see that the jest of the posts is that you need an abrasive to polish them, be it toothpaste or fine sandpaper. There was a TV add where they used a liquid and just wiped them clean. In the commercial, the person doing the cleaning was wearing latex gloves, which means the cleaner was probably a little caustic.
There are some other ways to go. I'm not sure what headlight lenses your 2003 Southwind has, but if they're off of a car like most RV lenses, you can simply copy the DOT number on the lens, do a Google search and you'll come back with the lens that was used, as an example, off of a 2001 Ford truck. My old Diplomat used a Buick Century lens. These lenses are relatively cheap online, usually $70-$100. If you have the old automotive replaceable lenses, you can just replace them with a higher quality new lens, giving you some better nighttime lighting.