I use lots of wood and treat it all the same. First I work to get the dry stuff but then I want anything that goes in my tank to be as safe as the dishes I eat off at dinner. So I do a bleach soak, just like my dishes!
The key points to know is the way chlorine works. It is bad for fish as it reacts with anything organic and that includes soft things things like fish gills or bugs/fungus, etc. So we want to let it react with the things we want to change and not the fish! It reacts with wood and tannin, so we use that info.
If we soak wood in water and add regular, cheap, unscented, uncolored bleach, the chlorine in the bleach will react with the wood,etc. until one or the other is all used up. Since we don't use a crazy amount of bleach more than a cup, the chlorine runs out before it totally eats the wood! After we soak it 8-10 hours, the bleach water may soak into the wood enough to react with all the tannin or it may not get that deep. Depends on the wood and how green?
But it is an easy thing to do and harms nothing except it will likely make the wood look and ugly white for a while until it get soaked in the tank and then returns to normal color. Once we soak it , take it out and rinse it to dilute any potential bleach left, then let it dry to give time for any chlorine to return to it's normal state as a gas.
Be careful not to get bleach on clothing as it will react with that, too. Hole city!!!
Onceit dries and we can't smell bleach, it is sterile and safe but whether it colors the water will depend on how much tannin is left. May work, may not?
I screw a piece of softer slate tile to the bottom to get it to stand or lay where and how I want it.