I would not use vasoline or any other oil or silicone based product near anything I am preparing to paint. These contaminants will ruin a paint job surer than ****. This is why any professional painter will tell you to use wax and grease remover before painting, making sure the surface to be painted is clean and free of contaminants. Skuff the surface, tape off areas to be free of paint, clean with wax and grease remover, use a etching primer and then paint. Although expensive,automotive quality paint will give the best results, and be the most durable. My two cents.