what you got there needs stripping down with nitro morse stripper with wire wool,then give it a good wash with hydrogen peroxide(weak bleach) then sand with very fine paper,i.e 1200 grit,then its up to you if you want to stain or go for the natural look.natural look is just oil,but lots of coats of teak oil,and stain is personal choice of whatever colour you want to go,recommend anything by fiddes,at least 3 coats of stain,the more you put on the shinier it will get,unless you leave it a few weeks between coats,another good coating is a product called diamond glaze,its a satin finish,very har