I know that this is a rather late response. But since I have recently created a website about carafes & decanters of all kind I feel that adding it here might be of some help and value to future readers. I also wrote about the different cleaning techniques, what to do and what not to as well as how to clean your wine decanter. Feel free to visit and I am glad about any critics or suggestions coming from you.
Anyways, from personal experience, I can tell you that that decanter cleaning balls are working rather well when it comes to removing stains. But it is most helpful if you give your decanter a good rinse right after you used it. If you leave it for awhile or even overnight, well, then you will have a hard time getting it clean. The decanter cleaning brushes are okay but not necessary I'd say. And if nothing helps I'd take a denture cleaning tab and put it in the decanter together with some hot water and leave it overnight. Result: As good as new!
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