Editors' pick: Originally published Jan. 24.

To drum up interest in its relatively non-creative new Big Macs, McDonald's (MCD) - Get Report has done something once unthinkable: it has given away its secret sauce in bottles for free.

McDonald's gave away 10,000 bottles of Big Mac special sauce this week tied with the release of its Grand Mac and Mac Jr. sandwiches. Each bottle is marked with a number, for you collectors out there. Except for special promotions in Australia -- and one very pricey bottle auctioned in the U.K. -- the sauce has been available solely in the U.S. on the company's waistline-busting signature sandwich.

The promotion kicked off on Thursday.

The Grand Mac, which rests on a larger sesame seed bun, is made with two beef patties that weigh in at one-third of a pound compared to a traditional Big Mac, which has two, 1.6-ounce beef patties. Think of this one as a supersized Big Mac. The Mac Jr. is a essentially a single-layer Big Mac, which may be more ideal for the hands of kids (great news, right?).

Each sandwich has the traditional Big Mac sauce.

We got our bottle. It was number 7,610 out of 10,000.

McDonald's started testing the Grand Mac and Mac Jr. in more than 120 restaurants in the central Ohio and Dallas areas last April.

The Golden Arches could certainly use the buzz likely to emanate from this publicity stunt.

Despite improving its food quality and expanding its popular all-day breakfast menu, McDonald's is still having trouble getting people through the door.

Mickey D's guest counts in the U.S. fell 2.1% last year it said on Monday. In 2015, guest counts in the U.S. dropped 3.0%. Guest counts in the U.S. haven't risen since 2012, when they gained 1.9%. U.S. same-store sales fell 1.3% year-over-year in large part due to tepid store traffic. Wall Street was looking for a 1.4% decline.

Clearly, McDonald's forgot to clean up the ingredient list of the special sauce, which has an eye-popping 32 chemically sounding ingredients. But, social media doesn't seem to care judging by the responses to the promotion.