Hm, I've got a couple of bags (- long and short kind) of the soft, cottony kind of old-fashioned pipe cleaners, you can easily get them here in DK. I use them for my lady pipes. And before you guys'll come up with any smart ideas, I can tell you that I only smoke 100 % pure Virginia tobacco in those pipes.
Try a large specialist tobacco shop online - I can't imagine that the stiff-bristle type of pipe cleaners'll do any good for the insides of an expensive collector's item kind of pipe, for example.
Cheers,
Maria.