Scrub it first with white spirit and wire wool to remove the surface crud then...
Use a power sander and progressively finer grades of paper - best done outside especially if married. Finish off by hand with a block and some really fine grade paper 400 grit say. Always sand in the direction of the grain and keep the power sander dead flat at all times else you'll make permanent hollows.
When satisfied with quality of finish wipe it down with white spirit or even just a damp cloth. Then apply a liberal coat of Teak Oil - let dry and apply another coat.
You may be tempted to varnish the table but if you do, wait a few weeks after oiling and wipe over again with spirit and use a matt varnish as a finishing coat - gloss varnish is ok for the first three coats (at least 24 hours drying and sanding between coats) but a gloss topcoat will just highlight any imperfections that the sanding failed to remove.
Peccavi
February 2009