Please consider the following helpful hints when opening mail at home or at work. Remember, the physical appearance of a mail bomb is limited only by the imagination of the bomber. Mail bombs have been contained in letters, books, and parcels of varying sizes, shapes, and colors. However, mail bombs often have exhibited certain characteristics which should be helpful in identifying a suspect item. To apply these helpful hints, it is important to know the type of mail normally received.
Letters feel rigid, appear uneven or lopsided, or are bulkier than normal.
Oil stains may be present on the wrapper. Use of excessive amount of postage stamps. The sender is unknown. No return address. The addressee normally does not receive personal mail at the office.