The Treasury Department is warning Americans to check their junk mail, because their stimulus money may arrive in a prepaid debit card.

The government is sending nearly four million people prepaid debit cards instead of a paper check, to get the money delivered faster.

However, some people are throwing the cards out, either not realizing what it is or thinking it's a scam. In order to activate the card, recipients are required to give personal information to an automated system.

The cards can be replaced, but there's a fee.

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