Is there any way to make glass bangles smaller?

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Someone brought me back glass bangles back from India (like this: http://alumni.media.mit.edu/~sarac/albums/objets/churiholder.sized.jpg) and they're a  bit big and tend fall off my wrists. And I was just wondering if there was any way to make them smaller? I was thinking maybe running a thick layer of resin (or something else?) around the inside might keep them from sliding off? Has anyone done anything like this before? Any other ideas?

TIA!