By October, he had numbered each jar and was down to the last one.
The company gave him another 72 jars after McKay posted a photo on Twitter with a countertop full of the empty peanut butter jars. It also issued a challenge to the teen to get 72,000 retweets for a free lifetime supply.
In January, McKay accomplished the feat.
McKay whose father is a furloughed federal employee, donated a pallet of the peanut butter, "a five-year supply," to other unpaid federal workers, WTOP reported.
"I like peanut butter," McKay told WUSA. "I don't need that much peanut butter."