Old Teak
Hi Ken!Sounds like it's just old teak that has been aged and darkened over the years with numerous applications of oils and other treatments.If it hasn't been varnished, there are several teak cleaners on the market that can be ordered from marine suppliers or be had at your local marina store. They all claim to be great, so you might wind up experimenting to find the one that does the job best. A lot of them have oxylic acid in them so be careful with your upholstry.If it's been varnished, your talking about stripping and sanding back to the bare wood finish. There will be a lot of elbow grease regardless of which finish it has.Yor other post regarding hand rails and hatch rails, try Rudy Nickerson at the attached site. He might have what your looking for.Good Luck!