What constitutes a suspicious letter or package?

Some typical characteristics which ought to trigger suspicion include letters or parcels that:
Have any powdery substance on the outside. Are unexpected or from someone unfamiliar to you. Have excessive postage, handwritten or poorly typed address, incorrect titles or titles with no name, or misspellings of common words. Are addressed to someone no longer with your organization or are otherwise outdated. Have no return address, or have one that can't be verified as legitimate. Are of unusual weight, given their size, or are lopsided or oddly shaped. Have an unusual amount of tape. Are marked with restrictive endorsements, such as "Personal" or "Confidential." Have strange odors or stains.

What Should I do if I Receive an Anthrax Threat by Mail?

Do not handle the mail piece or package suspected of contamination. Make sure that damaged or suspicious packages are isolated and the immediate area cordoned off. Ensure that all persons who have touched the mail piece wash their hands with soap and water. Notify your local law enforcement authorities. List all persons who have touched the letter and/or envelope. Include contact information and have this information available for the authorities. Place all items worn when in contact with the suspected mail piece in plastic bags and have them available for law enforcement agents. As soon as practical, shower with soap and water. Notify the Center for Disease Control Emergency Response at 770-488-7100 for answers to any questions.