Sometimes i get my hands on yacht equipment, interior and general repairs. Teak is full of resins so you cannot use varnishish or paint on it so oils are used, but you need to reoil wooden parts one maybe twice a year , especialy on boats. Teak can go grey really fast so it needs to be oiled. But no worry, you can restore it pretty fast. These days, you can buy product that will disolve grey resin and top part of oak, im using Bondex Renovation.
Just clean wooden parts with water and sponge.
Wait until its dry, then paint it with Bondex Renovation or other similar product and wait for 15m
Then use sand paper or even better sanding pads for sanding under water( im using SIA or 3M around 200 grit) and start sanding and cleaing teak, just wet the pad and wood, sand it, clean pad in water, use sponge to clean sanded wood and repeat.
After all sanding and cleaning is done, let it dry and use oil based finish.
and just for fun, one really old depth meter :D
take a look at my other projets @dantak maybe you will like them too ;)