try "scratch out"...it is sold at the box stores like Walmart it werks great on plastic/acrylic of any type and is inexspensive ...my Uncle brought his H/D 03 dresser to the shop last yr. and had some sort of water/mineral stains on the clear coat of his fairing he could not get off ..after tryin lottsa high dollar products he was P.O.'D.
just for tickles i grabbed the scratch out onna the boys had bought for there snowmobile windshiled...WHALLA with a few gentle rubs all the stains were gone.
Try it...
