Re: caring for cork handles?
Try cleaning it up with SoftScrub bathroom cleaner but understand that a lot of rods of lower price point both new and old use(d) crappy cork. I remain opposed to "preservative" finishes...let the cork bits fall where they may.
I've told this story before in detail but to recap: Seasons back, an old bud and I had identical Scott Pow-R-Ply 5pc. glass rods. On a trip up in the mountains, we left our rods rigged and my friend had simply leaned his against a Doug Fir in camp. Emerging from our tents in the morning, Don let out a yelp. Though the dog had apparently slept through this or, more likely, wisely shied away, a quill pig had, during the night, gnawed the cork down to the glue nubs enjoying the sweat salt on the cork grip. Now THAT is a cork grip problem.
If you want to see great new cork, look at G.Loomis's NRX rods featuring old growth, darkly figured, super dense cork. None of this typical soft pale stuff.