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Direct mail marketing glossary

Stay current with the latest direct mail marketing terms.

Nixie undeliverable mail

When mail is undeliverable, it is marked with a yellow label. A code will be printed on the label to indicate the reasons why the mail couldn't be delivered. Most often, the reason is a change of address, missing or incorrect address information, a vacant location, or a change of address that has expired (COAs last for one year). Nixies are another resource mailers can use to keep their address list up-to-date. When mail is undeliverable, mailers must update or remove the address in question.