I've tried a lot of "home remedies" and expensive stuff for clearing plastic lenses. They either flat out don't work, require way too much elbow grease, or simply provide an oily covering that is gone in a washing or two. I have had the best luck the old school way: a buffer and polishing compound.
As stated earlier. what ever abrasive technique you use, the protective coating is removed, so that exposure to the elements will eventually start to dull and cloud the lens again. I use Nu Finish polish wo slow this process down. I am a big fan of Nu Finish in the orange bottle, particularly for all plastic and fiberglass surfaces. You can apply it in the direct sun and it doesn't leave dust. It is a polymer material and contains no wax. It's available everywhere, and it's cheap (end of commercial).