I've used top tube protectors on fixies and track frames for years and found that you need to be careful of how you assemble them. I've used old tubular latex inner tubes, black inner tubes, etc., clear polyethylene tubing, etc., and they all pretty much release stuff that ends up leaving a nasty stain (if not worse) on your paint finish under the protector. So now I use some plumbers' teflon tape first, then some plastic tape to hold the teflon tape in place, and then I can put whatever I want as a protector on top of it. If you do it neatly, one layer goes right over the previous one so it just looks like a simple, very neat protector. The plastic tape over the teflon also helps protect the top tube from accumulating perspiration under the protector and eating into the frame. (I've had rust under top tube protectors as well.)