Chalky hands are the trademark of a GPP pullup day.
Hours after a GPP pullup day, you'll see chalky hand prints everywhere. You see them on the floor (especially if combined with pushups). You'll see them on cars in the parking lot. We once even heard of someone making a new friend while in a grocery store after noticing some chalky LuLu's. Yep, it was a peep.
Chalk can be VERY helpful. We use chalk a lot at GPP.
But, most of you aren't using enough.
Chalking your hands has the effect of making the implement, or bar you are using less slippery. This helps you stay connected to the implement (KB, DB, BB, Pullup bar) you are using. It also helps prevent fatigue. But the extra grippiness (word?) usually comes at a cost.
Use an ABUNDANCE of chalk. (see pic below)
The mistake most of us make is using just enough chalk to make our hands extra grippy. By using just a LITTLE bit of chalk your hands will be MORE grippy than you need. Having hands which are more grippy than you need is (we promise) the LAST thing you want. If you've ever ripped a callous or torn your hands, you know it's not something you want to soon repeat.
What you really need is a caking layer of chalk. Caking your hands with chalk will give your hands the grip you need for hanging onto stuff. Plus it will allow for the little bit of slippage you need to prevent rips and tears.