How to Remove White Rings
I have a round oak table and a walnut table that someone left either a hot cup or a cold wet drink that left a white round ring on the top of each table. Could you tell me the process of how to remove the white rings? - Bruce Van Cleave
Rob Johnstone: You could try rubbing a rag dampened with denatured alcohol very gently over the top of the table to see if that helps. If it does not, there is actually a liquid product sold specifically for removing white rings on furniture called Liberon Ring Remover.
Tim Inman: Success with white ring removal really depends upon knowing generally what the original finish was. Removing white rings successfully, without leaving blemishes or ruining the "good" finish is a professional skill. You can learn to do it, though!
First, identify the finish you're dealing with. If it was an older varnish or spirit varnish, then applying an oil-like spirits of camphor is often effective. Rubbing out, as Rob suggests, can work, too. An old household trick was to use toothpaste or ash as an abrasive with some mineral oil or even olive oil. With older varnish finishes, the white damaged area is usually only at the "top" of the finish coating. Thus, you can rub it out. If the finish is newer, or a lacquer/shellac type material, then I would suggest an alternative approach. Most lacquers can be "resolubilized" or re-dissolved; varnishes cannot. For these, you can usually effectively eliminate white water marks by applying an appropriate solvent and just letting it re-wet the lacquer and "presto" the white rings disappear. The lacquer re-hardens and you're out of the doghouse and back in business. Of course, while the solvent is active, the finish is liquid or nearly liquid again - so with this approach DO NOT do any rubbing or even touching while the work is in process. How do you know what you have? Test a small area in an inconspicuous place before you proceed. Lacquers are dissolved with lacquer thinner, fingernail polish remover and sometimes alcohol; varnishes are usually not - at least they will hold out longer. If you determine your finish is newer and/or lacquer type, then one can actually purchase an aerosol blush remover and spray it over the affected area (also see Rob's suggestion above). Follow the label instructions, of course. Worst comes to worst: refinish the top, and get a big stick to train your friends with.