At least you don't have 'shaggadelic' mohair hanging off the overhead! I remember a Reinell 26 that did....
Some of the teak cleaning products around might lighten the finish first.. lots of the older 'oiled teak' interiors get pretty dark over time.
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"