Police say potential victims can guard themselves against a "grandma scam" by paying attention to a handful of clues. Here are the most important: How much does the caller know about you and your family? Ask questions about the supposed family member and other relatives that only a few people might know, then wait for the response. Check the area code from where the calls originate. Many area codes in these scams do not exist in the United States or Canada. Ask the caller where he is calling from, and see if it matches the code on your phone. If you don't recognize the area code, hang up. Any request to send money via a wire should trigger an immediate alarm, especially if relatives are not overseas. If one of the scammers professes to be upset with your refusal to cooperate, hang up. Ignore pleas not to tell anyone. Such pleas are used to create fear.