i know this is old, but in case any of you were wondering.. i used a white paint pen. it worked brilliantly. was the most painless job i did on my car, that made a part look 1000% better, that i have ever done. cleaned the 3 caps really good, with eagles foamy tire and wheel cleaner, shot a really thin coat of dupli-colors gloss black lacquer on top of the power steering cap, then painted all three caps' lettering with the paint marker. it took a steady hand, but they came out PERFECT. they look brand new, factory, and only cost me 2 bucks, for the paint pen. if any of you want this done, cuz you may not have a steady hand, send your 3 caps to me, and i can most likely make them look brand new.