Glass Chatroom Board

Today, I noticed some tiny black specks, about the size of pepper, on a piece of antique clear glass. I never noticed it before but it's been in storage for many years. Today, I washed it in soap suds and rinsed... spots still there.. then tried 1 tablespoon in enough water to cover the top of vase (turned upside down in a bowl) now I am trying vinegar water. I have used a soft scrubby after each soaking except this one that is still soaking. I am getting nowhere. I can't think what caused the tiny black specks. About a month ago, I fastened some bubble wrap around the vase & fastened it with scotch tape & stored it in a cardboard box in the spare room. I did not notice the spots when I re-wrapped it a month ago in bubble wrap & scotch tape around the top and bottom to fasten it.. Before that I had it wrapped in newspaper. I wonder if the scotch tape caused it?

So what do you think caused the tiny black specks and how do I get rid of them. Thanks for any help.