yellow color left on glass container

I am new to this forum and I hope to find information related to colloidal siver. I ran across an article on the net by Mark Metcalf and I've made the generator which works fine. Using a pint jar filled not quite to the top I leave the generator on for about ninety minutes which makes a light brown liquid and turns to a nice dark yellow or amber color after several hours in the dark.

My question is I store the Colloidal Silver in a clear glass jar in the dark but within a few days the glass becomes stained with a dark yellow color that easily washes off. Any ideas on what is causing the yellow color on the inside surface of the jar and should I try to get it back into the solution?

Thanks for any help.