Hammerite? Sorry - unhelpful comment i know. I usually use autosol too or if you're really bothered about it suggest getting your pipes prefessionally polished or cleaned. It may be wise to renew the wadding too as others have indicated whist you're at it to help prevent future discolouration.

Hmm, anyone toyed with getting their pipes colour coated/anodised or however it's done? I'm thinking jet black matt pipes would look stunning on a dook.