NEW WATERFORD, N.S. -- Police have asked Canadians to be on the lookout for old money, after thousands of dollars in vintage bills dating back to the 1950s were stolen from a Cape Breton home.

The cash -- bills in green, orange and other bright colours that have long been out of circulation -- were taken from a New Waterford, N.S., residence between July 18 and Aug. 21.

Police say the homeowners were away and returned to discover thousands of dollars had been stolen, including the vintage bills -- mostly $20s, $50s and $100s.

Cape Breton Regional Police released a photo of old-style notes on Friday and asked anyone who sees bills like them in circulation to contact them.

"We want people to be aware of what it is that they're looking for," said police spokesperson Desiree Vassallo.

"There's probably a lot of people who haven't seen bills from this time period, it was actually before I was even born. I myself haven't seen these either except for these pictures."

She said the bills had not been simply stuffed between mattresses -- they were collectibles passed down as a family heirloom.

"We don't think there's anything that would prohibit somebody from actually spending it, but it would probably be on a case-by-case basis in terms of a retailer choosing to accept it or not," she said.

"If it did make its way through to a retailer, at that point the bank would likely take it out of circulation if they noticed it."