Think of a wet wooden handle like a sponge. Simply wiping the surface does nothing for the moisture trapped inside.
To dry your knife properly, wrap the handle in an absorbent towel and press gently around the ferrule and joints. Avoid twisting or excessive pressure; let any remaining surface moisture air-dry. Trust us, that extra 10 seconds matter.
Pay attention to the join: Water can collect around the ferrule and the point where the tang enters a traditional wa handle. After washing, use a clean, absorbent towel to dry those areas carefully rather than simply giving the knife a quick shake.
You can wrap the handle in a dry towel and gently press to absorb surface moisture, but don't twist or force it. Avoid leaving wooden handles submerged, and let the knife finish drying in a well-ventilated place before storing it in an enclosed saya.