Florida Police have found a missing elderly woman with dementia and it’s all thanks to her foresight — rubbing a pad under her arm, roughly two and a half years ago.

When the elderly woman went missing, she spent two hours away from her home. Police said she was endangered. Fortunately, she’d made a scent preservation kit — a sterile gauze pad with her odour, inside a closed jar — dated Jan. 19, 2015,  which police dogs used to track her down.

Sealed with tamper-proof tape and stored at room temperature, the pad keeps the person’s scent for seven years or longer.

The scent preservation kit allowed police to find the woman in less than five minutes, the county sheriff’s office wrote on Facebook. “The woman was returned home safely and K9 Ally was rewarded with a special treat, a tasty vanilla ice cream cone!”

Manufacturers of the scent preservation kits said some call them “insurance in a jar,” as the kits are even more effective than clothing and other personal items. Because the kits are not contaminated by other people’s or the environment’s smells,  the missing person’s smell is isolated. That means police dogs can more easily find the missing person without confusion.

BBC reported China, Germany and others have used scent preservation kits to track people with varying degrees of success.

Earlier this month, the Citrus Country Chronicle reported, local police have been working to get more vulnerable people like those with dementia or autism to set up a kit in case they go missing. On July 11, the Chronicle reported “to date, 5,000 kits have been distributed throughout Citrus County. More recently, the police force have begun a voluntary registration system, so when people go missing, the police have their scent on file, the Chronicle reported.

The sheriff’s office could not be reached for comment.