You could go extreme and get a snad blaster
You could try boiling water, it might loosen it up enough to break free from the wood. Other then that it would seem manually picking, scraping, or rubbing it off are your options. If you used sandpaper it may discolor the wood in places but it will darken back up soon enough. Cellulose is a tough substance and you are going to have a hard time finding anything to 'dissolve' it, bleach sure won't.