You could get a small quantity of these graphite powder from the hardware store to try out. They are in a tube and exactly the same thing. Otherwise google it. Blick's, Jerry's art store and even Amazon carries it.
I did a few experiements for you, Lee.
In general, I use it for monotone drawings with large backgrounds of dark and I smudge it with paper towel. I put newspaper on my table so it's easy for clean up. To erase, I use kneaded eraser or the Sakura electric eraser.
General's Graphite powder and the tongue has Cretacolor Aquastic colored on top of the graphite and then washed.
Pentalic 70 lb sketchbook 5.5 x 8 inch
These are done in the same sketchbook.
This one is just pure graphite powder and a bit of pencil for the small details of seeds inside the pod.
This one is some scraped cheap watercolor powder from a Michael's palette mixed with the graphite powder and a couple drops of water it gave me a really nice green.
Very rewettable and liftable. Not good to do layers of different colors in this type of sketches. It will muddy up. But with just one color, it gives you a lot of variety, plus add more dry powder swipes in the end.
The best tool to use for smooth application in medium coverage is the pan pastel handle with sponge tool - even and non messy. I've tried other cosmetic sponges before and they just keep dropping powder everywhere.
For large spaces, still use paper towels. For really tiny spaces, use paper stumps, tortillons.
This one has a layer of graphite powder first and then I put the wet cheap Michael's watercolor on top. Surprisingly, this graphite powder once laid down with this sponge is very stable and it doesn't migrate to other areas.
This one is Daniel Smith Blue Geniune Apatite tube watercolor mixed with a bit of graphite powder. It gives a very strong mixed blue and very rewettable and liftable too.
Also used Kimberly 9xxb pencil to do some details.