In the 1920s, Guinn recovered one of two grindstones used in the Graham Salt Works, an early enterprise begun by city founders, Col. E.S. Graham and his brother G.A. Graham. They were the salt work's third owners and upgraded the business into a flourishing enterprise, operating from January 1872 to 1873.
Guinn Sr. owned land around Salt Creek where he found the grindstones down in an old cistern. Edwards said after Guinn moved to a home on Summitt Street, the grindstone sat in his front yard for many years.