Electric Wire Insulators--These used to be atop all electric poles to protect junctions. When new, the glass was clear, but turned blue with age. Now they are collectible. Thanks to to my Great Aunt Jewel.
I love blown glass so much, and I've always wished for old-fashioned perfume bottles to come back in a practical sense (I mean, I could use them, but it's such a pain to transfer from the commercial bottle to your own!)