Whenever I heat silver (sterling or fine) to annealing temperatures,
I do it in a regular "room" atmosphere using a torch.
You didn't say whether you're using sterling or fine silver, so I'm
However, any time you heat sterling silver to annealing temps, you
will get a change in the surface structure that will "cloud" it
(bringing the fine silver toward the surface by depleting the copper
in the alloy) -- and likely outright oxidation. Pickling following
annealing is always required, in my experience.
I can't think of any case where annealing would be the final
finishing step for a piece; you'll always be pickling and doing final
polishing after annealing and shaping. Am I missing something in
what you're trying to do?