If you’ve got kids, you probably have watermarks on your finished wood table. Since they may never listen to your pleas to use a coaster, use a little petroleum jelly to remove the white stains. Just rub the area with the jelly and let sit for several hours (or even overnight). Then rub again with a soft cloth and the stain should disappear.
From: Who Knew? 10,001 Easy Solutions to Everyday Problems by: Bruce Lubin & Jeanne Bossolina-Lubin