Heat up to cherry red and plunge into cold water/pickle. That's
how to anneal sterling.
It might be useful, too, to define cherry red. It’s often
misunderstood in these days of artificial lighting in our studios.
The term came into use back when we heated things over a dimly lit
charcoal furnace, on an otherwise dimly lit room. And the red
described is that very dark blackish red that some cherries have, not
a bright red. In bright light, you can’t see it glow at all. The
temp is around 900 F. If you’re really seeing the silver glow in an
environment with decent light, such as a normal jewelers bench these
days, you’re actually getting it hotter than it needs to be, and
perhaps getting some grain growth. this won’t affect fabricated
work, but it can reduce the malleability and strength of metal you’re
forging. And in quenching sterling, if it hits the water while you
still see any significant glow, you can easily shatter it.