I've seen burnt-out bulbs used as a base for a variety of knitted things-usually Christmas decorations. A girl I knew in high school had an older sister that did this.I think this was a thing of the '70's,-making decorative things out of household junk. On the same order,I saw burnt-out bulbs being used as fishing bobbers(or crab-trap markers)when I lived in Florida. The guy wove a net around the bulb out of nylon string.(He told me he did it for net-making practice,which was a hobby of his). Wish I'd asked for one. They looked sorta cool,especially after "aging" a bit in salt water.