dont use nail polish remover, it may muck up the plastic. scrape the glue off in small chips/flakes with an exacto or similar held perpendicular to the lense, and lightly scratch at it, touch only the glue, not the lense, the glue will flake off. If the edges have turned white, toothpaste is an extremely fine abrasive and may remove the white (dont ask, if youve been there you know what I mean).
Check with the store. Mine can be cleaned with acetone, and that is the solvent for crazy glue. I strongly advise against using a knife to pick it off; you will either not get it off or you will ruin the lenses.