mkay, good to know.
"Chalk is important to good hand safety. It keeps the skin dry and tight, making folding under a load less a problem. You should apply chalk before you start training every day, for all the lifts. If you gym is one of those that does not allow chalk, for reasons of cleanliness or whatever, you need to reevaluate your choice of gyms."
(Starting Strength 2nd ed. p. 109)