I am currently rolling a car. But as a test I want to compare the color I using to a color I have in a 1 gallon can of Dupont Lucite lacquer paint. It's been sitting unopened for a long time. I was going to try a small patch sprayed with my HPLV gun but wasn't sure if the paint would be any good. How long can an unopened can of automotive lacquer last in a cool dark place??