As George says, a bit of alcohol should do the trick. A two minute stylus should look like a ball and not be chipped or have flat spots. Check using a powerful magnifying glass or a watchmakers' eyeglass (obtainable from eBay cheaply). If the playing surface of the ball is damaged it is possible to soften the adhesive using heat and rotate the stylus with fine tweezers, but this is tricky and I have never attempted it. I normally send the bar to Expert Stylus and they put a new sapphire in.