Cleaning driftwood with black hair algae

Boiling water usually does the trick if you don't want to go with the bleaching method.

Do you have a pot big enough to completely submerge the piece. I ask because when I boil wood I boil it to the point where it is so hot that when I take it out of the water (using oven mits) the exterior of the piece actually dries from the heat. Then I let it stand until cool enough to place into the tank.

You can also bake the wood in an oven at low heat for an amount of time. Bake it long enough for the entire piece of wood to be hot. Just don't bake it at a temp that it too high or you will have a fire hazard on your hands. Make sure not to leave it or the room while baking. Wood can be a hazard even at lower temperatures.

One other method that has worked for me is freezing. I have have stuck BHA infested wood outside during a Montreal January night then rinsed it off in the morning under hot tap water. Worked well but not as well as the boiling method.

You could also try keeping it in the dark for a few days - that should accomplish much the same thing as a blackout on a tank; algae will die off without light. Boiling's a good idea too