Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
I would not worry too much about it, but if you want to clean it off, then start with gentler tools so you will not scratch the branch that you will be putting back into the tank.
You could try gently lifting any loose edges and pulling to see if you can get more of it off.
A plastic scrub brush is less likely to scar the wood than anything stiffer, but if you have to use a wire brush, then keep working in the direction of the grain. That way, when it does scratch, at least the scratches will be lined up right.