I find for the tape those Magic Erasers work well or just change it out to a color for sanity. What keeps my bike easy to wipe off specks of dirt (it is blue/white/black) is using Pedro's Bike Lust. It keeps the frame kind of waxed and then I can use a micro fiber cloth to gently wipe her off where she looks a little better. I don't wipe anything dry that might scratch and use a soft cloth.
I use unscented baby wipes for post-mountain biking clean up, I wonder if those would be okay?
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan