When silver starts to react with sulfur the first color to appear is
a yellowish tint. It gets darker and darker with increasing exposure
eventually getting very black.
It sounds like you gel is old or just very weak. I have never used
Winox. you probably should add some more H2S - either try the old
hard boiled egg in a box method or use another material.
I could tell you other ways to make H2S but shouldn’t–too much is
toxic.
It is really bad when you can no longer smell it ! Liver of sulfur
solid goes bad after aging in air and especially so after it is
mixed with water.
Don’t worry about removing the yellow first. try the Winox.
jesse
heat and pickle will remove the patina; otherwise as far as I know
abrasives are your best bet.
if they went yellow, either the LOS was understrength/old, you
didn’t leave them in long enough, or they were dirty 
from what I hear of the gel, it works well - you could try cleaning
them really well and dipping them again?
sophie
It sounds like it might be old. Maybe you haven’t had it for a long
time, but the stuff has a shelf life, and it may have reached it.
I don’t use the gel, but the solid stuff, breaking off what I need
and doing my best to wrap it back up airtight. When I see that it
doesn’t disolve well, then I know that it will take a loooooong time
to oxidize silver. It will eventually (give it an hour or two). The
first color you get is a sickly yellow, that goes golden, then on
through the colors. Never quite the dark blue-grey of fresh stuff,
though.
If you haven’t had it long, let Otto Frei know, so they can do
something about the product.
best regards,
Kelley
It sounds like you gel is old or just very weak. I have never used
Winox. you probably should add some more H2S - either try the old
hard boiled egg in a box method or use another material.
What is the hard boiled egg in a box method?
decomposing eggs give off hydrogen sulfide. just put a broken up
hard boiled egg in a box with your silver. An old egg is better.
The silver will get black. I have mentioned here several times how
my daughters silver went black very quickly while silver is very slow
to tarnish in mine. We live in the same area her house was new and
mine about 20 years old then. I finally think I have found out why.
During the building boom about 10 years ago there were a lot of
houses built with wall board from CHINA.
This has been identified with lots of H2S emitting from the
wallboard. The problem is big in Florida - we are in Texas., but the
construction timing is right and the effect would be the same.
A thing that made the problem stranger was that Florida produces so
much Gypsum. We are not in a strong industrial pollution area
either. I do think her house had a lot of Chinese wallboard in it.
She built a newer house nearby- I haven’t noticed the problem with
that one YET.
jesse