Millions of dollars in New Jersey Lottery prizes go uncollected every year, so if you play the lottery on a regular basis, you may want to go back and check your tickets.

Lottery jackpots displayed at Quick Chek in Lawrenceville (Dan Alexander, Townsquare Media NJ)

"In the fiscal year that just ended in June, we had about $38.5 million worth of forfeited prizes; the year before, it was about $37.8 million," said Carole Hedinger, executive director of the New Jersey Lottery. "The numbers are pretty consistent year-to-year and it's unfortunate, but it's generally made up mostly of small prizes that people didn't realize they won, like $5 or $10."

It's unusual, but sometimes larger, multi-state prizes remain unclaimed as well. That means some leftover money has to be split among those states.

"When each state sells a multi-state game the prizes are paid, for everything but the jackpot within each state, from the sales of that state," Hedinger said. "Only the jackpot money gets pooled for the jackpot prize."

Further complications can arise if no one matches all the winning numbers, but the states have a system in place to address this issue.

"In the event that there is no winning ticket and it expires, then each state gets back a prorated share of the forfeited prize based on their sales," Hedinger said. "It's a formula that is used by the multi-state organization to calculate what each state would get back."

The fate of unclaimed prize money varies depending on location.

In New Jersey, a portion of the money is used to fund additional prizes. The balance is returned to the state.