+1, you have to take the grips off. Do it carefully and they should be fine to glue on again. If the rubbing alcohol won't break the glue bond, try Bestine (art supply) or lighter fluid (like for Zippo or Ronson, not BBQ) or Naptha (hardware store). Also sounds like the levers you have don't have the correct clamp loops (they come in at least 2 sizes, usually stamped right on the steel) cheaper to get the right ones than new levers.