I've never understood the obsession (so common among fishkeepers) with boiling, bleaching, blah, blah, blah...Most of the time, that's just a waste of energy, time and bleach.
You have a few decent-looking chunks of wood, fairly gnarled and twisted, and they look like they have been drying and weathering for some time. Bleach is a disinfectant; do you truly believe that some virulent fish pathogen has survived the sun, the wind, the drying-out...and is just lurking in that wood like some weird aquatic Egyptian curse, waiting for you to put it into your tank so that it can re-animate itself and wreak havoc on your Oscars? The possibility exists...almost any possibility exists...but the odds are pretty long. If you are worried about that, then you should probably wear a hardhat when you go outside, in case you are struck by a stray meteorite, or perhaps a frozen poopsicle falling from a passing jumbo jet. The best way to remove bleach from wood is to not put any on in the first place.
I'd soak those dry dessicated pieces in a few changes of water and then blast them with a pressure washer; you can do it in a car wash if you don't have one, just don't use soap or let the wood sit in soapy puddles on the concrete. Soaking will give them a head start towards becoming waterlogged, but you'll likely still need to tie and/or weight them down for awhile before they sink. Soaking will also give you an idea if they are going to release significant amounts of tannins.
If the water starts to look like weak tea, you have two choices. First, you could go into full MFK panic mode and start buying exotic filtration media to remove the tannins, set up a witches' cauldron and start boiling the chunk of wood, and start a few threads labelled "HELP!!!" and beg for advice. Or...the better choice...accept that tannins are actually helpful rather than harmful in terms of fish health. If you just don't like the colour...I'm with you on that one, I hate the way it looks. But there's this interesting and mysterious practice that dates back to the early days of aquarium keeping; it's called "changing water". Hopefully you are already doing this regularly. If you are, the tannins will be removed and diluted with every change; eventually they will stop leaching out, and your water will remain clear. Crisis averted!
Right about now someone will start warning you about certain species of wood containing toxic compounds. Yes, they do exist. If you cut a branch off a Eucalyptus tree and throw it into your tank, your fish will likely die. But that's why it's important to look for wood that is long dead, and has been weathering and de-toxifying naturally. If you are able to determine the species of driftwood and know that it is safe, that's great. But frankly, I never worry about this; an old, weathered, wind-beaten piece of driftwood is something I will use without hesitation; after more than 5 decades of using carefully selected DIY driftwood in virtually all my tanks, my fish have yet to fall prey to a piece of killer wood.
Relax; be patient. If you rush things, if you go out bound and determined that you will find a great piece of wood today, but you don't find one so you grab a questionable one instead...you'll probably still be okay...but why risk it? Driftwood is called that because it is wood that has been submerged and carried by the water and then cast up and dried, sometimes repeating that cycle many times for long periods of time, and that's what makes it safe to use. A close second choice would be wood found in a desert environment, again, old and dry. Don't grab wood off the side of the road, or from your neighbour's burn pile, or from a half-dead tree in the park. That's not driftwood; it's just garbage, and although it is likely safe, there is a bit more risk involved in its use.
Good luck, let's see how that tank looks with those nice pieces installed. But the pieces that look like twigs you found under the tree in your yard after a windstorm? Pitch 'em!
