I get the digest, so I'm always a bit late and you'll have heard this
by now, but for heaven's sake, don't scrap your work just because of
a little firescale! I think I'd have thrown away about half of the
stuff I'd done if that were the case.
Firescale just means that finishing will take a bit longer - if it's
in an area that can be treated in such a manner, sand off the
outermost layer of the piece with sanding sticks or discs and
repolish. You should be able to see whether the firescale is gone
when you reach the tripoli stage. If it's still there, hit it again
with the sandpaper. I find it usually doesn't take much sanding to
get rid of it.
On highly contoured or textured pieces, you might take the opposite
approach and try to cover the whole piece evenly with firescale.
This will give it a greyer appearance than usual, but this is not
always unattractive - on an oxidized, "baroque" piece, it can
actually add to the overall finish.
You can also heat and pickle the piece to raise a layer of fine
silver - just be careful not to polish through it. I've only
succeeded in using this technique by accident (really happy
accident), so any finer tips that y'all could share would be