There is probably a really easy answer to this but it's early and I'm only on my first cup of tea
Talc is often used as a drying agent, especially on babies (Accidentally covered my little girl last night after her bath) so why isn't this used in place of chalk. Would work out cheaper than a ball of chalk, I'm sure
I wasn't being flippant, just put it on your hands, the feel of it should be enough - it's like making your hands into wet flippers. Worth filling up your mates chalk bag at the wall but good for nowt else climbing wise.