Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
That looks like it is already weathered and ready for use.
Yes, clean off the dust, soak it until it sinks.
Breaking off the little twigs can work just fine, but you might end up getting out the pruning shears for slightly larger pieces. If you figure out what orientation works best, then cut off the ends, make the cut at a bit of an angle, and in a way that is not visible from the front.