I've heard of various ways of getting rid of them. Many of which have been mentioned already. I had a large one and didn't fancy getting the scissors out, so I tried the cottom method. You have to tie it quite tight (uncomfortable for a few minutes, but soon you can't feel it at all), and thenMost just leave it. After 24-36 hours mine had swelled slightly and turned purple. Within 3-4 days it had shrivelled and turned black. I eventually could just twist off what was left after about 6 days. Smaller ones will usually be quicker at coming off.
Can't believe I spent years with it when it was so easy to get rid of!