I put mine in a ziploc
I did put mine in a ziploc when I bought a gross, never seemed to matter though.
Years ago I tried the oven dry thing on some master. It made the blue go on a little dryer, more like the green. No other changes. Then I found a cube that I had accidentally left on my open patio for months. South Louisiana, it had soaked up as much moisture as it could. I tried it. It played just fine but was kinda gummy.
The abrasive added to chalk is what makes it work. As long as you get a layer of abrasive between tip and cue ball, nothing else affects play.
Hu