help/tips to remove stain from minotti leger coffee table  

Hi people,
I have a fairly old Minotti Leger coffee table that i bought used...the previous owners didn't really take allot of care for the the table as it is covered in stains and coffee cup circles (i asume it are stains from spilling coffee or some other beverage. (see attached image)
I was hoping someone could help me out or give some tips on how to remove these stains...i tried soda and also vinegar (some tip i found online) but without the slightest succes.
The table is the "Plate version"
the Frame is in solid iron and top finish in lapped plate.
All help is more than welcome