Yesterday, I got a vintage 1961 Buick Wagon that I got from E Bay in the mail. It's nicely done and slightly hot rodded out. However, the windshield and back window that are one piece were painted over in flat black paint and I wish to remove it without harming both considering the plastic is over 50 years old. Any tips, advice or a line on a product that'll do the job is greatly appreciated. It's something that I haven't done before.