As i look through, my binder has so many backs of mailer's i've received and scribbled on. cant figure why.
Is your mailbox a short walk from where you normally work? Walks have been credited for the assist in idea generation from Aristotle to Nietzsche (and beyond).
I personally just keep a little pocket notebook and a couple pens on my person at all times. That replaces the need for the distributed folders of your system. Every week I go through and add them to either my paper notebook or my digital notes.
I don’t really trash the “bad” ideas either since my notebook is bound. I try to be neither precious with the good ideas nor embarrassed of the bad. I treat them all as just a record of thoughts.