The following comments were found on old newspaper clippings stuffed in a 100 year old book.
The source of the clippings is unknown.

Water Spots

Please tell me how to remove the gray spots from my walnut chairs left from water dripped on them.
Mrs. P.B. Indiana

ANSWER:
Fill a pan with tepid water and add a few drops of household ammonia. Dip a soft cloth in the water, wring as dry as you can, then hold on the white spots. It may require two or three such applications. When the spots disappear, rub the surface well with furniture polish.