Yesterday I bought a brown glass blob-top beer bottle. I believe it had been dug up because of the condition of the outside surface. It had what looked like a deposit on the surface.
I tried these materials to clean:
rubbing alcohol, Bar Keeper's Friend, Brillo pad, turpentine, carb & choke cleaner, rubbing compound and Meguires auto polish. Nothing worked.
Then I tried Toro mower T-150 coating liquid. It worked perfectly.