User talk:Tonycls

Hi, I wonder how can I clean up stubborn marks/blemishes or turn a headlamp's cover(made of polycarbonate material) from brownish to crystal clear & transparent - possibly like the new one. Believe me, I'd tried using all kinds of cleaning agents sold in the market, they all failed. Any other methods that you can recommend ? Would soaking them into soaped hot water overnight or using bleach helps ? Honestly I haven't tried this yet for afraid it can spoil the lamps cover. Please suggest. Thanks, have a pleasant weekend.