I've read that people use powerheads to blast at the foot of a nem to make it uncomfortable and peel off on its own, but that doesnt seem feasible with something as small as a mini. I have also read of people using ice and placing it at the edge of its foot to get it too move, but I havent ventured to try that.
I just picked a mini carpet nem up from the LFS and he just peeled it off but was really gentle. It was super sticky and even stuck to the bag on the way home!