The leather has seemed to darken up a fair bit since I first got it, but I haven't treated the handle with anything. The only reason I can reckon is a combination of hard use and lots of moisture from all my kayak trips and getting caught in the rain a few times. The handle seems to be a glutton for punishment haha, but I will be surprised if the thin leather holding the plastic sleeve on to the nylon backing of the sheath survives through the winter. Ah well, maybe it's the kick in the behind that I need to go get a proper sheath made (the factory one is garbage IMHO )