Give the wood a good scouring and wash. Dry. Microwave maybe, probably not necessary. Birds in the wild will nibble on whatever woods are native to their area, but they have built-up resistance to native microorganisms/bacteria that indoor birds do not. I don't keep things perfectly hospital-grade sanitized/anti-septic simply because Mochi's immune system would be weaker for it. Lastly, obviously, don't let them chew wood that's been stained, polished or waxed.