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
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.