I was reading ETS's list for an altoids tin personal kit and saw that tape was used to make the lid into a signal mirror. This prompted me to do a web search for "mirror tape" and I got hits. Here's the first: http://www.identi-tape.com/deco-mirror.html

Has anyone tested any for use as a signal mirror? From the picture it looks a lot like duct sealing tape, only shinier.

Can't say that I have, since for less than the cost of a roll of shiny tape, I could get a real signal mirror - mine fits very nicely into the lid of an Altoids tin. If I had some tape on hand, I would probably paste it on a convenient surface. It would surely be better than nothing.