SAN FRANCISCO (AP) — To get you come into McDonald's and buy new versions of its Big Mac, the chain is giving away 10,000 bottles of its trademark special sauce for people to use at home.The move is to celebrate the introduction of the Mac Jr. and the Grand Mac, two different-sized variations of the classic sandwich.The giveaway is a first in the United States.McDonald's introduced the Big Mac in 1968. In 1975, the special sauce got its own call out in the signature Big Mac commercial, touting the burger's components "Two all-beef patties, special sauce,lettuce, cheese, pickles, onions on a sesame seed bun."The bottles will be available Thursday at participating locations nationwide.Additional details on how and where customers can get their hands on a bottle are expected to be released later Wednesday.