I've used an old card to flat pack duck tape too. Word to the wise, you should probably avoid the wallet carry. That's how I carried my tape, and my body heat caused the glue to melt. The duck tape was permanently attached to my wallet (had to cut it out) and left my wallet a gummy mess. I'm not going to ruin another wallet trying that again.

You could also wrap up a needle in the duct tape on the card for safety purposes, or even a razor blade.

Wrap the needle or razor blade in a bit of waxed paper or parchment paper 1st to avoid a dangerous (perhaps bloody) attempt to extract it!