For my stylus I do have the original B&O brush that came with my BG3000, which I have used (though very gently as I am afraid of damaging it). For my records, I bought a kind of block thing that looks like a board duster from school (if you're old enough to remember such a thing) which is covered in a kind of velvet fabric. I have used both and while I'd say there is a small improvement, it still sounds poor. I have checked the stylus tip with a strong magnifying glass and it looks clean, so i am starting to think it is actually damaged.
I also have an MMC5, much older but still working, and when I exchanged the MMC4 for that, the sound was much better if not perfect (but I wouldn't expect it to be - the MMC5 was last retipped many years ago and has had a fair bit of use since then).
Location: Liverpool
My B&O Icons: