It's old news that the federal government spends billions of dollars on wasteful programs, services and regulations each year, as Sen. Tom Coburn's annual "wastebook" recently demonstrated.

But each year, tax dollars also pay for programs, property, equipment and supplies that literally go unused.

As a result, billions of dollars go up in smoke without so much as a study on romance novels to show for it. Here are some of 2013's worst examples, as reported by the Washington Examiner:

• By far the costliest is the $1.6 billion it takes each year to maintain almost 100,000 empty and underused federally owned buildings.

Poor management and a tangle of bureaucratic rules makes it near impossible to get rid of unneeded space quickly — if a few years can be called "quickly."

• Sometimes federal property gets wasted by being left out to rot -- literally. Employees at a U.S. Postal Service processing plant in Maryland left important mail equipment worth $1.3 million sitting outside in the yard that should have been stored inside.

One mail tub crumbled at the touch, which a USPS engineer told inspectors would take years of outside exposure.

USPS lost another $30,000 worth of mail loaders in Atlanta. Some were stolen, some destroyed and some simply couldn't be located.

• The Postal Service isn't the only one leaving its property out in the cold. The Department of Defense wasted at least $2 million on 774 official vehicles that sat in the lot unused or barely driven. A Ford truck that costs $4,700 to lease each year was driven a grand total of 37 miles.

• A failed nuclear enrichment company got a $30 million green energy loan from the Department of Energy -- two days after it announced it was filing for bankruptcy.

Worse, there is no market for the technology United States Enrichment Corp. has been struggling to create using mostly taxpayer money.

• Overlapping programs also waste money, and often none of them produce the desired results, Tom Schatz, president of good-government group Citizens Against Government Waste, told the Examiner.

There are more than 200 federal science, technology, engineering and math programs designed to improve American students' aptitude in these areas, which foreign students dominate.

Despite the programs, which cost about $3 billion each year, science and math achievement scores aren't going up, Schatz said.

"We're creating more programs that aren't working," he said.

• In Afghanistan, the U.S. military presence may be declining, but the waste is not. A $34 million Marine Corps command center built at Camp Leatherneck was supposed to accommodate the troop surge, but remains unfinished as those troops are leaving the base.

• There's also $500 million worth of military transport planes now sitting unused on the tarmac in Kandahar after the Afghan National Security Forces barely flew them and couldn't afford to maintain them.

• The Defense Department also sent $133 million more in radio equipment to Afghanistan than ANSF needed, leaving the expensive parts sitting in storage.

• More than $21 million has gone up in smoke at bases where DOD had trash incinerators built, but never used them.

"The overriding thing is just the complete mismanagement of the taxpayers' money," Schatz said.

While "waste" can be applied to programs some people want to cut and others think are important, mismanagement applies to overspending across government, Schatz said.

Congress pours money into programs without reining in costs. "They don't solve any problems, they just keep spending the money," he said.