Thanks for all the replies so far! I ordered the filter from B&H just a few weeks ago, so I'll have to give them a call and see if it's still under warranty or anything. As for the glue, it had the consistency of rubber cement when it came off. There is no type of retaining ring or anything else holding it in place. I'll give B&H a call and see where that gets me, if they can't help I'll try Schneider Optics next.