The later '26 and '27 were avail with factory option of "natural" or varnished wood spokes. Don't use bleach as that will attack the wood fibers. The very best is to use paint scrapers. You can buy them, but the cheap and fast and sharpness are shards of plate glass. If you have an old windshield or window glass from your T, that can be wrapped in an old towel, smash the glass, and use the long tapered shards of glass to scrape the wood clean.
Have done that lots of time, then sand lightly, and coat with diluted spar varnish, steel or bronze wool between coats after dry, or light sand if you get a run, then continue with more coats of varnish, each less diluted until you get to full strength coat.....