[ic] Purging session/ and tmp/ - expireall, or rm?

[ICdev]

Hey,

I'm not quite clear on which method I should use in crontab to clear the 
contents of the 'session' and 'tmp' directories.

In the icadvanced document, it says that if you're using DBM sessions, you 
should use expireall. I am using standard session files, but having searched 
the archives, people seem to be using expireall or plain old rm arbitrarily, 
or even both, one after the other!

So, which of the following should I use?:

20 4 * * * su -c "/usr/lib/interchange/bin/expireall -r" interch

or

20 4 * * * find /var/lib/interchange/store_name/session -type f -mtime +2 | 
xargs rm -fv
20 4 * * * find /var/lib/interchange/store_name/tmp -type f -mtime +2 | xargs 
rm -fv

, or doesn't it matter? Shouldn't the parent directories of the session files 
be deleted too?

I tried expireall manually - it took its time executing, but didn't seem to 
have any affect on the stuff in session and tmp; I'm guessing that's because 
it's less than a day old.

*Finally*, what if someone is placing an order just as their session files are 
deleted with rm?

Thank you in advance.