Handle treatment
Asking the manufacturer is always best, but here is one approach that I know has been used successfully to refurbish the leather ax handle. It works on any similar hadle made of leather rings.
Start by removing any traces of the old vanish top coat with fine sandpaper. Clean with saddle soap or Lexol leather cleaner and a little water to remove surface soiling, then wipe clean with a damp cloth, and allow to fully dry. Next, wipe down with a small amount of a highly refined neatsfoot oil such as Fiebing's. Resist the temptation to use too much of the oil, as it can promote breakdown of the leather fibers. Allow that to soak in for a day or so in a warm place.
Next, work in a liberal amount of Lexol Leather conditioner. Allow this to penetrate overnight (again in a warm place), wipe away any excess the next morning, and set aside for a week. These steps will ensure the leather does not rot, but obviously cannot repair any damage present if the handle has been neglected.
At this point, you can either (1) give it a topcoat of a beeswax product such as SnoSeal (which can be periodically renewed), or (2) finish with two coats of a quality polyurethane (sand lightly between coats). If you apply the wax, warm the handle gently with a hair drier, and soften the wax by placing the can in warm water.
This is a good time to clean and polish the metal, and true and sharpen the edge with a file, followed by finishing with a whetstone disk and honing oil. Check for instructions on Youtube if you are unsure about how to do this.
Yes, this is a bit of trouble (and then some). But your axe will be handsome again, and fully ready for another 10 or 20 years of use with just a little touch up now and then. Just use common sense in storing it! I keep a very light coat of RIG rust preventative grease on the metal, the same as I do with many other tools. A thin film is all you need.
My grandfather, who lived to be 97, spent his early years as a lumberjack (pre-WWI), and later worked as a foreman/master carpenter and mechanic, and drummed into my head how to properly care for tools. As a result, many of them are still perfectly serviceable today.