WASHINGTON — Ever swiped a pen, tape gun, letter tray or a mail tub from a post office? The U.S. Postal Service would like it back, please.

Starting today, the cash-strapped delivery service said, it is giving customers two weeks to return stolen equipment, no questions asked.

The USPS spent nearly $50 million last year replacing equipment that was stolen or inadvertently taken and never returned by customers, officials said this week, labeling such thefts “a serious issue.”

“We are in a financial crisis and simply cannot afford this type of unnecessary expense,” said David Williams, vice president of USPS network operations. “The equipment is federal property, and we want it back.”

The Postal Service is aggressively cutting costs with plans to close thousands of post offices and hundreds of mail-processing facilities. Observers expect that next week it will announce losses of at least $10 billion for fiscal 2011.

It is a federal crime to steal postal equipment, and doing so can lead to up to three years in prison or up to $250,000 in fines.

The U.S. Postal Inspection Service said that with more than 32,000 post offices and more than 200 mail-processing facilities nationwide, the USPS uses thousands of pallets (costing $20 each) to move crates of mail, letter trays ($2.75 each) and translucent mail tubs with “United States Postal Service” emblazoned along the side in black letters ($4 each).

Postal inspectors have recovered more than 200,000 pieces of equipment worth more than $4 million since 2008.

One of the worst offenders was a Georgia man who worked for a major mailer and was arrested for stealing and selling almost 10,000 Postal Service pallets to a pallet supply company, according to postal inspectors. The company, in turn, provided USPS equipment to a freight company shipping to South America. The man paid $10,129 in restitution to the Postal Service.

A Florida man once sold more than 21,000 pallets. After he said he was aware that it was against the law to steal and resell the pallets, he was sentenced in federal court to five months in prison and ordered to pay more than $419,000 in restitution.