I have a vintage guitar that was once white, but now its pretty much in the cream / yellowish realm. And I bought some cream knobs for it however they are still much whiter than the rest of the guitar, and I was wondering if there were any tricks to getting the knobs to be a little dingier and yellower. I thought of maybe submerging them in a coffee can for a week or wrapping them in wet coffee grinds. But that might make them brown or just look weird. Theres gotta be some easy way to do it though.