Spread a layer of petroleum jelly over the white spots. Be sure to cover the spots completely, overlapping a little on the edges to remove all of the spots.
Let the petroleum jelly sit on the wood overnight.
Wipe the petroleum jelly away with a soft cloth. If any white spots remain, reapply the petroleum jelly and allow it to stand overnight again before removing it.
Clean the wood with furniture cleaner and a soft cloth once the white marks are completely removed.