White marks are usually caused by moisture in the finish. There are myriad cures for this. In no particular order:

* mayonnaise smeared on and left overnight. I cannot vouch for this approach, as I've never tried it.

* Padding with proprietary products meant for this or denatured alcohol. Lightly dampen a rag and lightly wipe in a sweeping motion. With the right finish, this works well.

* Special stain removal cloths. You can find these in Lowe's, some ACE hardware and some Bed, Bath & Beyond. Normally sold as stain or white ring removal cloths. This is what I use and have never had them fail. The only issue is that it will result in a glossy surface. I dull this down with rubbing or the right sheen lacquer once I have the spots removed. A similar approach is the "baby oil and cigarette ashes" that provides a very light abrasive grit in oil.

* Blush remover aerosols. These are lacquer thinner in a can that re-dissolves the lacquer and lets the moisture blush escape. You will only find these at places that cater to professional touch up people and finishers.

Thank you very much for the solutions to my table. It is a beautiful table but these problems seem to be popping up quite frequently. So thank you once again.

When you get the white marks off....give the table a good coat of paste wax to prevent that from happening again....repeat the wax about every 3 months depending on the use it gets.
Linda d

Wax provides virtually no protection against moisture. Do not confuse beading up (a surface tension phenomenon) with moisture exclusion.

From Flexner's Understanding Wood Finishing, 2d ed.,P.129 (section on shellac finishes)

"Myth
You can protect shellac from water damage by applying a couple of coats of paste wax.

Fact
Wax slows water penetration only if it is left thick (as on the ends or boards in lumber yards), or if it applied to a perfectly smooth surface such as glass. Although it's possible to level and polish a shellac finish almost perfectly smooth, in practice you can't count on any protection from wax. First, it's rare that you have such a smooth surface. And second, once that surface has received even a little wear, minute gaps will develop in the wax that will allow water to pass through."

And p. 254, chapter on furniture care:
"But wax, applied thin as a polish, has no significant retarding effect on moisture exchange."