Avoiding the "Items Obtained" Rankings

A bunch of tricks have been posted here to avoid the solo attack times and battles cleared rankings, but I haven't seen any techniques to avoid the items obtained rankings.

If you bot a lot, you pick up a lot of leather/cloth/enhancement stones/etc. from the boss drops, and it's easy to end up on the items obtained rankings as a result.

Does anyone know of a good way to avoid those rankings?

Haven't tried it, but in theory, having a full inventory might impact that. I know everyone loves cleaning out their mailbox.

Edit: Apparently doesn't work. Meh.

What are those techniques?

It counts even if it goes to your mailbox. Just deal with it, the items obtained/ap used/etc reset every day. It's really just the battle times that don't reset