I have been restoring/refinishing wood articles for the better part of 50 years and I believe I've literally tried everything under the sun over that time.
For the past few years I've been using Howards "Restor-A-Finish" on everything from an 18 Century grandfather clock case, to pieces of furniture to multiple gunstocks with both oil and varnish finishes. It does an excellent job of getting discoloration out of the finish including white rings in furniture. The producer maintain it's a finish penetrating restorer that blends out existing scratches while cleaning the surface. You just put some on 4/0 steel wool and gently scrub the surface. I use a relatively stiff toothbrush for the checkering.
This product is readily available in multiple tones at Home depot or Lowes.
Jim
N.B: There are probably as many different answers to the original question that started this thread as there are members of this forum. My response is based upon personally trying what has been proposed so far multiple times over the years.
Last edited by italiansxs; 10/08/13 06:03 PM.