Depends a bit on what the finish is.

If it's laquer or poly you can rub with rubbing alcohol and sometimes
it will evaoprate it out. Not good if it is shellac.

Alternatively, you can rub with mineral oil and try to displace the
water with oil on any finish.

On Apr 6, 10:56*am, (Dennis Obrien) wrote:
Hey, does anyone out there know how to remove white water and heat
stains from oak furniture??
* *At one time I knew how to easily do this, but I seem to have
forgotten.
* *I would appreciate it if anyone can clue me in, short of refinishing
the entire thing.
* *Thanx, Dennis