This report covers treating plant run No. 15, June 25 to June 27, 1951, in which a cold sulfuric acid treatment was applied to the composite total naphtha produced during cracking plant run No. 33. This naphtha was a mixture of material from the thermal cracking of a total coker gas oil and cracking of a heavy gas oil and was treated to provide more data on cracked stocks and to determine the minimum 66 degree Be sulfuric acid treatment necessary to produce a finished gasoline of satisfactory sulfur content, color, gum content, and storage stability.