FWIW, this guy uses straps in training.
http://www.ironscene.com/videos/1454..._training.html
edited to add - I should also plug my chalk idea- kid's sidewalk chalk. You can keep it in your pocket or bag and rub it on your palms as needed. It doesn't get on the floor, so the gym employees don't throw a hissy, and it costs about $.23 per. Plus, you can use pink and other colors that make people look at you funny (if you're a guy). I have green now, so I feel like the Hulk.
Seriously though, it works.