Bill Clinton reveals why Secret Service gave him an M&M's box

*Video shows the Secret Service providing a look inside its ink lab.

(The Hill) -- Former President Bill Clinton says the Secret Service helped him mark a fitness milestone when he was at the White House with a candy-coated memento that he's held onto.

"I went running every morning for years," the ex-commander in chief said in an interview with USA Today published Monday, while promoting the political thriller he co-authored with James Patterson, "The First Gentleman."

"I still have the M&M's box that I was given by the head of my security detail on my 100th run when I was president," Clinton said.

"I loved it," he told the newspaper.

"Once M&M's get 20 years old, you don't eat them anymore," Patterson quipped.

Retired Secret Service agent Nick Trotta recalled in a 2012 interview how