Another unlockable mystery of life

A pile of old keys looks like a pile of promises that something special can be unlocked. But who knows what locks all these keys can open? The basket holds at least 50 keys--keys to cars I no longer own, keys to I don't remember what doors--but I don't dare get rid of them because what if I need them someday? Somewhere in that mess is the key I know I need right now, but how can I possibly tell which key fits that lock? Someone should go through and label all the keys, or discard the ones we no longer need, but who has the time? If only I had the key to unlock that mystery!