I'm afraid I'm a bit confused... You say that your script by itself takes less than a minute to run. So, what's the evidence (in fact, what's the big deal) that there's any sort of memory leak? I mean, if it finishes that quickly, why worry about it?

Now, if there's a problem that it's producing bad output in some way, then there's something to fix, but I still don't get the relation between something like that and an idea that there's a memory leak. How about showing some of the evidence, and/or some of the code?