Finding the common denominator between Scranton, Pennsylvania; Akron, Ohio; and Winston-Salem, North Carolina, might seem like an impossible equation. But their similarities lie in one intriguing quality: their wealth of secondhand treasures . According to a recent analysis by Elemental , a precious metal refiner, the three urban areas are among the best US cities for antique and vintage shopping, ranking first, second, and third, respectively. Vintage finds at Mongers Market in Bridgeport, Connecticut Photo: Bekah Wright/Connecticut Post/Hearst Newspapers/Getty Images To determine the rankings, Elemental analyzed data from 100 of the largest US cities, focusing on 11 factors that contribute to antiquing potential. This included number of vintage stores, the average star ratings of secondhand shops, online search interest, and what percentage of population is over 65, among other qualities.…