How can I make Corten steel rust faster?

Corten steel rusts naturally through exposure to the elements, but if you want to speed up the process, you can treat it with a mixture of water, salt and vinegar. Spray or brush this regularly onto the steel and allow it to dry outdoors. Repeat until the desired rust layer has formed. Make sure the steel can dry sufficiently between treatments, as it is the alternation of wet and dry that accelerates rust formation.