Here is a new one for $50 [ame="http://www.ebay.com/itm/Mopar-70-71-72-73-74-Dart-Windshield-Washer-Bottle-To-be-Used-With-Foot-Pump-/380590772436?pt=Vintage_Car_Truck_Parts_Accessories&fits=Model%3ADuster&hash=item589cfa50d4&vxp=mtr"]Mopar 70 71 72 73 74 Dart Windshield Washer Bottle to Be Used with Foot Pump | eBay[/ame]
I've heard that you can put that type of plastic in boiling water and it will bring some of the whiteness back. It's also supposed to make it not so brittle. It won't work miracles though. Maybe worth a shot?