It 's weird Val, you almost have to keep on top of it daily. Everytime I send one, I go in and clean out as much of the un-necessary sent/received as possible. Be sure to change the "Show Messages From" timeframe for the standard 5 days, to, The Beginning". Also remember to delete your sent ones, but be cvareful not to delete the ones people haven't read yet.
Now, I thought that once you become an "I Support RC" member, your mailbox grows...But I am not sure if that is true. I'm gonna ask about that one.