A white ring or mark on your red oak furniture is a telltale sign of water stains, which occur when moisture is absorbed into the wood. The resulting white stain may appear to be permanent, but you can remove it with some household items and restore your red oak furniture to a clean, appealing condition. To remove the stain completely, it must be drawn out of the wood.
Dampen a clean cloth with water. Sprinkle a few drops of ammonia onto the damp cloth and use it to wipe up the water stain on your red oak furniture. Buff the stain for a minute or two with the cloth then dry the surface.
Place a dry cloth over the remaining water stain. Heat your clothing iron to "Low" and place it on top of the dry cloth. Leave the iron in place for five to 10 seconds at a time so the heat from the iron can draw the stain-causing moisture out of the red oak wood.
Treat any remaining stubborn water stain with a paste made from equal parts of white toothpaste and baking soda. Smear the thick paste over the remaining stain, allowing it to sit for a few minutes before you buff it with a clean cloth. Repeat this step until the water stain is completely gone.
Wipe down your red oak furniture with a damp cloth. Dry with a clean, dry cloth.
Place coasters or place mats beneath hot or potentially wet dishes to prevent water stains. Another option for creating a cleaning paste is mayonnaise mixed with ashes (cigar or cigarette).