Electro etching silver black oxide

When electro etching silver I am getting a black oxide on the silver
that seems to slow down my etch, can someone point me in the right
direction? Am I going to get this no matter what?

When electro etching silver I am getting a black oxide on the
silver 

What electrolyte are you using, Shawn? I have done quite a bit of
electro-etching on silver, using either dilute nitric acid, ferric
nitrate solution, or just plain silver nitrate solution. I usually
end up with darkened surfaces which I clean up with a glass-fibre
brush. A recent alternative, useful for small hard-to-reach places,
is a kind of alumina needle, made from alumina powder bound with
fibre-glass.

Paul Jelley
London

When electro etching silver I am getting a black oxide on the silver
that seems to slow down my etch, can someone point me in the right
direction? Am I going to get this no matter what?