Dead Letter Office

A dead letter office (DLO) is a facility within a postal system where undeliverable mail is dealt with. Mail is considered to be undeliverable when the address is invalid so it cannot be delivered to addressee, and there is no return address so it cannot be returned to the sender.

At a DLO, mail is usually opened to try to find an address to forward to. If an address is found, the envelope is usually sealed using tape or postal seals, or enclosed in plastic bags and delivered. If the letter or parcel is still undeliverable, valuable items are then auctioned off while the correspondence is usually destroyed. Despite this practice, in the past some undeliverable envelopes were acquired by philatelists.

Dead letter offices go by different names in different countries. Other names include returned letter office or undeliverable mail office.

Canada Post sends mail which is not deliverable to the Undeliverable Mail Office (NUMO) at Mississauga, Ontario or North Sydney, Nova Scotia. Domestic mail which is still undeliverable after passing through NUMO is then destroyed, while incoming international undeliverable mail is returned to the country of origin.

In Malta, undeliverable mail was sorted in the General Post Office in Valletta. The facility was initially known as Returned Letter Branch, but later on it was also referred to as Returned Letter Office or Dead Letter Office. Various postal markings were used at the facility from 1889 onwards.

A Dead Letter Office was first established in 1784 for dead and missent letters that had reached London. The bye-letter offices dealt with bye-letters and those that did not go to London. No postage was charged for returns, which were made after six months, where an addressee was found. From 1790 a charge was made for returned letter but the time was reduced to two months by John Palmer. Upon hearing of the return charge William Pitt rescinded the charge.

In the UK, undeliverable mail is processed in the National Returns Centre in Belfast which holds 20 million undeliverable items, or in a smaller office in Portsmouth.

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Wikipedia