The Proofgrade has a finish on it. The edges…hang on a second, and I’ll run a quick test…
Okay just splashed some water on fragments of the cut cherry and maple - water beads up on the front and back surfaces. Water also tends to roll off of the charred edge. (Maybe from the resins in the wood.)
If you wipe the water off, a little bit of char does come off on the rag.
So unless it is left sitting in water, I’m not going to worry about it too much. You can always seal the edges with something like Krylon, dilute wood glue or varnish though, if you’re concerned about it getting knocked into the sink.
I’ve been using it for a few days and it’s held up fine. (YMMV)