Every year, tens of billions of dollars worth of unclaimed tax refunds and other financial assets languish in government coffers.

As of March last year, the IRS still held an estimated $917 million in unclaimed federal tax refunds for 1 million workers who didn’t file taxes in 2009.  And tax preparation company H&R Block, hoping to capitalize on consumers’ laxity, launched an ad campaign this month encouraging them to "get their billion back."

In addition to unclaimed tax refunds, state governments are holding onto nearly $42 billiion worth of unclaimed property (uncashed paychecks, insurance payouts, unused bank funds, and the like), according to The National Association of Unclaimed Property Administrators (NAUPA).

One in four Texans has money with their name on it at the state comptroller’s office, where $3 billion worth of unclaimed property is collecting dust. California is holding on to more than twice as much, with $6.4 billion worth of property belonging to an estimated 21.5 million individuals and organizations.

New York blows both states away, holding more $12.5 billion worth of unclaimed property belonging to some 30 million people and businesses. Some of that loot belongs to mega-celebrities like Beyoncé, Tina Fey and Angelina Jolie.

If multimillionaires with teams of accountants on staff can’t even keep track of their finances, imagine how easy it can be for the rest of us to let unclaimed property slip through the cracks.

"We're not talking about free money here," says Pete Sepp, Executive Vice President of the National Taxpayers' Union. "This was money that an individual or a family earned and gave too much of to the federal government. They should get it back."

How do you find out if you’ve got money with your name on it waiting to be picked up? And how soon do you have to act? Here’s everything you need to know:

Unclaimed tax refunds:

The IRS is great about tracking down people who didn't pay enough taxes, but it's not like they'll go out of their way to contact people who are actually owed refunds. The only way to get your refund is to file a federal income tax return.

Most of the unrecovered refunds held at the IRS come from people who didn’t think they earned enough income to file income taxes, even though federal taxes were taken out of their paychecks. Others may have forgotten that they qualified for tax breaks like the Earned Income Tax Credit, which is reserved for low-income earners and can be worth more than $5,000.

And on top of that, thousands of income tax refund checks are returned to the IRS as undeliverable, meaning the check was returned because the taxpayer moved, changed names, or simply wrote the wrong address, according to the National Taxpayers Union.

"These days, a name change perhaps if you get married or divorced is a more common reason [for an undelivered refund check]," Sepps says.

The simplest way to prevent your refund from getting lost on its way to your mailbox is to sign up for direct deposit rather than having the IRS send a paper check.

By law, there’s a three-year window to recover unclaimed tax refunds and you can do so by filing a federal tax return. The last date to recover refunds for 2010 will be April 15, 2014.  If you miss the deadline, you can basically kiss your cash goodbye — it officially becomes property of the U.S. Treasury.  Certain exceptions apply for people who can prove they’ve experienced a mental or physical impairment.

Unclaimed state property:

Unclaimed property can include things like uncashed paychecks, stocks, checking accounts, insurance payments, certificates of deposit and expired gift card balances.

When money goes unclaimed or businesses can’t track down customers at their listed address, state laws kick in to protect that cash from going back to the companies themselves, according to the NAUPA. Companies are forced to turn the cash over to state governments, which keep the property safe and take it upon themselves to track down their rightful owners.

The best place to start looking for unclaimed money in your name is through the national database, MissingMoney.com, which lets you search by state for free and has been endorsed by NAUPA. You can also contact your state’s unclaimed property office directly. The good news is that, unlike federal tax refunds, most claims can be filed in perpetuity — even heirs of people who left cash behind can file claims to recover it. But be sure to check your state's laws, which can vary based on the type of property and how long it's been unclaimed.

"Some states can have fairly aggressive laws with what they do with unclaimed financial property," Sepp says. "It behooves the taxpayer to call the state right away or go online right away to find out."

There are businesses out there who claim to do a better job tracking down your unclaimed property for a nominal fee, but don’t buy their sales pitch. Unclaimed property information is always publicly available for free.

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These people earn six figures and still feel broke

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