hello guy & gals,new and first time to write in so excuse any mistakes ! I bought a 67 buick wagon that I want to use as my delivery horse at our upholstery shop, but it sat next to trees for about 10 years,the windows are so water stained so bad that I have tried everything that I can think of to get them clean, but I can still see some water stains,any ideas no cleaning or do they make a cleaner that might do the trick.