Beautiful Coffee Table How Can I Treat/fix A Stained Wood Coffe Table?

How can I treat/fix a stained wood coffe table? - beautiful coffee table

I have this coffee table from my father, and a picture of her beauty. Its all natural wood, never painted, dyed or treated. Everything was natural. The support provided by metal legs with two drawers and the top is open, a Tray 3. The lid is screwed up. I thought if we just leave the top and the table when my only concern is that the holes on the side where the top is screwed in all an idea to what was done to the table is? I would treat stains, but they are water stains on the cups, we have created it. What can I do to fix the table?