Sandblasting works great to get the crumbly parts off and give the wood a nice even texture. Just type "sandblasting" into google maps with your city and state, example
Sandblasting Pensacola, FLCall them up and ask if they can help with your project.
I find it best to use drift wood as it is fully dead and dried, driftwood also naturally hardens, whereas regular dead branches may be rotting inside.
Once blasted it's a good idea to bake the wood at about 200ºF (to kill mites and other pests that might be lodged in the wood).
Here's a pic of some sandblasted ghostwood aka driftwood
