Thanks for all the tips guys.
This is what they looked like after brushing on some Harpic
Looks like my Arrow pipe has cracked again on the other side. I'll have to get it welded up and get a brace put in between the two pipes. The wise Bibio foresaw this happening last time it broke
Then tried the coke and aluminium foil treatment which further improved them. I think they might come up good with some polish now
I've still to do the cat section too