White rings or spots on furniture are often caused by trapped water vapor under the finish. Given time to dry out, many fresh white rings will disappear on their own as the vapor is absorbed by dry air. If it does not disappear, gentle methods can be tried like using steel wool with lemon oil along the grain, toothpaste on a cotton towel, or Vaseline rubbed and wiped off. However, if the moisture has penetrated the finish, refinishing may be required.