Master Bowling make this powder called "Easy Slide". You just put a few dabs on the sole of the shoe helps you slide. The problem why it's not sliding is because humidity has got to the sole and that powder mops up any moisture. You could experiment with baby powder as well.
Use a wire brush in a lengthways motion, ie toe to heel. For your future benefit, if it starts to slip too much you can reduce the slide factor by brushing the sole sideways.