The spell of change metal to wood should work on rings and wands: it turns any metal ring or wand into a randomly selected wooden type of ring or wand. (Note that there is currently only 1 wooden ring). If the wand of wishing happens to be made of wood in the current game, it can’t be randomly chosen.

For wands, it works the same as polymorphing, so the resulting wand will keep its charge count, but of course unlike polymorphing it can’t be repeated since the wand will no longer be metal.