I would always boil my bogwood, more to get rid of tannins than anything else. The only time I didn't boil was on a piece of redmoor root which ended up getting what you have. I would take it out and place in a large pot and boil for a while, this should help remove any spores that are in it. If you don't have a pot big enough, place it in a sink or bath and pour boiling water over it, not as good but should help.