David,
Do not worry about the anodizing, very few masts are anodized. Even if
it is, it would take some very special arm waving to get the inside to
anodize at all.
Good Luck and keep us posted.
Matt Colie

wrote:
Hi there,

There's been lots of talk about putting foam in Ally masts - any ideas
on getting it out - previous owner of boat foamed in wires - PU foam
injected through 1/4" holes at about 6ft intervals. I now want to
replace these, and revert to internal halyards. Mast is 28 ft and only
access is from foot end. I had considered using plastic pipe with the
end cut like a holesaw and twisting, anyone got any other ideas that
won't ruin the anodising?

Thanks in advance,
David. SY Colros.