Stains on wood: citric acid
Remove stubborn stains on wood with citric acid.
If normal cleaning does not help anymore, you can treat the wood surface with citric acid and remove the stain with it. Finally, wash thoroughly, as there is a risk that the wood will continue to fade.
For example, red wine can also be removed with bleach (bleach is up to 3% sal ammoniac mixed hydrogen peroxide.)
Before treatment, the manufacturer should be asked how sensitive the wood surface is to the bleach, as otherwise dark wood may cause unsightly bright spots.
