The letters, which are more than a decade old, are being sent on with a label explaining the mail "was delayed."
The U.S. Postal Service isn't one of the offices that will be affected by a shutdown, but it will be following a holiday schedule.
UPS and FedEx will be operating normally though.
The president's latest attack was aimed at billionaire Democratic donor Tom Steyer on Sunday after he appeared on CNN.
The likes of Ann Coulter, Dinesh D'Souza and Rush Limbaugh have promoted the idea that Democrats sent mail bombs to key Democratic figures.
A special agent for the U.S. Postal Service Office of Inspector General said the former postal worker resigned in September.
The mail was also addressed to "Mr. Getout Ofengland."
The U.S. post office worker allegedly said he held onto some items for years, but focused on important deliveries.
A new mapping system divides the world into 57 trillion geotagged locations, each with a unique three-word name.
Whatever the reason for the large number of vacancies on the USPS board, this is no way to run a railroad—or a post office.
Unknown jihadists attacked a luxury hotel in November, killing 20 people including many foreigners.
Rural congressmen object to shuttering post offices. But cutting daily deliveries is a nonstarter.
Something must be done to avoid a collapse of USPS that would entail a costly taxpayer bailout.
New York Times investigation reveals a growing and unchecked Postal Service surveillance program