Always used Magic Eraser.
Got suckered into buying the Onzow, when it first appeared on the market. I guess mine didn't have enough "stickum" on it because there were times it didn't remove whatever gunk was on the stylus.
Declared it audio junk and tossed it aside.
Went back to Magic Eraser. Makes a dirty stylus come out like new.
I wouldn't be surprised if it leaves some of its "magic" behind, but I don't hear it.
After a couple dips, a few wipes with the cartridge brush, and it's good to go.
A $5.00 box is more than you'll ever need. The rest of it cleans the kitchen, bathroom and whatever.