my LFS cleans all its decor in bleach, lets it soak, then rinses, adds fresh water with double dechlorinator, and everythings cool. they've been doing it like that for years. i've cleaned my betta tanks with bleach, let it dry completely, and never had any problems. just make sure you either let it dry completely (not good with driftwood because it would take FOREVER to dry, and your trying to get it full of water anyway) but if you added the bleach right away, then added the double dechlor not long after that, maybe an hour, it would kill anything ON or in the wood, and the dechlor would get rid of the bleach (make sure its chlorine bleach). add another dose of dechlor every week and let it soak for a good long time, like a month maybe. by then, all the bleach should have evaporated or been neutralized by the dechlor (change the water periodically, like every week)
OR, you could take it out of the water completely, just scrub it really well with bleach in the bathtub, remove any loose pieces of bark of chunks of wood that are flaking off and scrub out all the nookes and craneys with bleach (no soap though!) and then rinse really well, then drop it back in fresh clean water with double dechlor and let it soak.
that second way would be safer if your concerned about it. i'm just thinking bleach because you can neutralize it with dechlor, it kills EVERYTHING, so it will kill any bugs, bacteria, or parasites on the wood, and if you use the second way, its only touching the outside and wont have any time to really soak into the wood and you can just rinse it off, then use the dechlor to remove any traces that might be left.
you could also use vinegar. just dump a few cups if vinegar in the garbage can with the wood and let it soak. rinse it really well and clean out the can after a couple days and let it finish soaking, change the water every few days or once a week.
but you should still scrub the wood really well to get any loose bits of bark off that bugs might be hiding under, and clean out any small nooks and craneys stuff could be hiding in.