a solution that might fix some batteries

i recieved 4 extra batteries in the post today. one was a dud. it wasnt wrapped properly so i figured it got bashed around in the post. i dropped one once on the stairs and it stopped working imidiately. they seem fragile. then i thought of blowing down into the LED end. i heard like a a small crack or a spark-like noise. the light came on. now it works just as good as any of them if not better. i label all my parts as to what date i recieved them on etc so i will update if it gives up any sooner than the others. anyways..this trick might work for some of your broken batteries out there..let me know.