I know we've already beat this subject to death, but I found a new tape at the hardware store today. It's called "friction tape", and is used among other things, to wrap hockey sticks. It's very sticky, and very flat black. I held it to a flashlight and stretched it, but no light came through. To make it even less reflective, you can stick another piece of tape to the top side, then pull it off. This causes little ridges to form, reducing reflections.
John
