Okay so I've been using chalk for deadlifts and shrugs for the last few weeks and I have definitely noticed something. Assuming you aren't trying to lift a huge amount of weight (I'm liftin at most 395lbs), it should be noted that using the chalk with a standard olympic barbell that had very pronounced metal "bumps" on it for grip did not work as well as the same type of barbells with less pronounced bumps on it for grip.

The first time I used chalk to deadlift, it worked very well and I had hardly any problems with my grip. About a week later I used it again on a barbell and for some reason it hurt my hands to the point where I couldn't do another set. The pain in my hands was keeping me from being able to perform the target amount of reps (only 5 or 6 reps).
Looking back at the barbells later I noticed the the very small bumps for the regular grip protruded a lot more on the barbell that hurt my hands than it did on the barbell that worked fine.
Using chalk, on certain barbells I found it hard to even shrug ~335lbs whereas deadlift on other bars at 395lbs was painless.

So when using chalk, if you notice that your hands are in pain from the grip then take into consideration what the 'bumps' on your barbell look like. Just thought I'd give you guys a heads up, especially those who haven't used chalk yet or are looking to start using it.