Big Mac special sauce available for $18K

Fast-food giant McDonald's is giving Australians the opportunity to buy a special bottle of the sauce used on their famous Big Mac - for at least US$18,000.

The 500 ml "Limited Edition Big Mac Special Sauce Bottle #1 of 200" is being auctioned on eBay with all proceeds going to charities run by the global chain to help sick children and their families.

"This bottle is #1 of only 200 being produced worldwide, and they won't be sold in restaurants," the eBay ad reads, adding that the sauce could be used to improve anything from goulash to cupcakes.