Dan Salt was a Seattle-based manager and promoter. He reportedly he was the brother of Lonnie Austin. July 20, 1925 Seattle Daily Times
According to the July 22, 1925 Spokane Spokesman-Review newspaper, Caruso (Dan) Salt had come from Philadelphia circa 1910 to Seattle and partnered with Austin in 1914. They operated the popular Austin and Salt boxing facility in Seattle. Salt also considered staging shows in nearby Tacoma in 1917. 
By 1914, he apparently spent his summers at his home on nearby Bainbridge Island. 
Salt died July 22, 1925, 1:40, of complications from peritonitis surgery at Providence Hospital, Seattle. He had lived in Seattle for 12 years, coming from Philadelphia as a representative for a saw and mill machinery manufacturer, according to the Wenatchee Daily World, July 23, 1925, p. 9.