If mailbox storage is consuming too much space, you may want to consider deleting stationary:
1. Use Window Explorer to navigate to \Program Files\Common Files\Microsoft Shared\Stationery.
2. Create a new sub-folder, \Program Files\Common Files\Microsoft Shared\Stationery\old.
3. Move all of the stationary, except Blank.htm and Blank Bkgrd.gif, to the \old sub-folder.
New messages will be several hundred KB smaller.