I got 2 pieces of driftwood from Petco tanks. First peice washed with brush and rinsed it with boiled water, after I was keeping it in bucket in bathroom (dark place), changing cold water everyday. For a week.
After added it to tank. It has been in a tank for a week or more now and it looks very pretty and clean, no algue.
Another piece I just rinsed twice in boiled water. That piece has some algeu on it right now.
I would reccomend to soak your wood for a week in dark place, changing cold tap water every day. If there is any fungus it would show up and you could clean it more.