 But if you're trying to paint galvanized metal, you'll need to take a rag, saturate it in white vinegar, and rub the metal down first. The acid in the vinegar reacts with the galvanized metal, etching it so the spray paint will stick to it. Just be sure to pick a day with little or no wind and cover the surrounding area so no overspray gets on your roof. I'm Danny Lifford with tips for today's homeowner.