Abstract: A decontamination bag is positioned in the interior space of a public mailbox. The decontamination bag receives mail that is deposited in the mailbox. A postal worker, upon retrieving mail from the mailbox, closes the decontamination bag. The decontamination bag is equipped with an exit valve and an intake valve. Air from the interior of the bag may be sampled for contaminants that may be carried by letters or mailpieces through an exit valve. A decontaminating agent may be introduced to the interior of the decontamination bag through the intake valve. The contents of the decontamination bag are thereby purified within the bag. After decontamination, the contents of the decontamination bag may be purged and fresh air may be reintroduced into the bag. The decontamination bag may then be opened in order to retrieve its contents.