No matter how careful you are, water stains happen to wood furniture. Thankfully, you can usually get rid of them with a liberal application of mayonnaise. No really.
Whether it's from an overwatered plant, a condensing drink, or a spill, water can leave wood furniture discolored if it's not cleaned up right away. Fortunately, there's an easy, non-destructive method that might help you remove those water stains: all you need is a jar of mayonnaise.
Just cover the stain with a generous smear of the popular sandwich condiment and let it sit anywhere from an hour to overnight. Clean it up and polish the piece with some nice furniture oil. The mayonnaise won't harm the wood, so if it doesn't work, you're only out some mayo.
How to Remove Water Stains from Wood [Sometimes Homemade]