Laboratory tests were performed to examine the efficacy of various leach treatments for decontaminating dissolver residual solids (KEACRESID1) produced during a 24-hour dissolution of K East Basin floor and Weasel Pit sludge composite in boiling 6 M HNO3. The starting dissolver residual solid for this testing, KEACRESID1, is a visibly heterogeneous material. This material contains radionuclides at concentrations above the ERDF Waste Acceptance Criteria for transuranics (TRU) by about a factor of 3, for 239Pu by a factor of 10, and for 241Am by a factor of 1.6. It meets (is below) the ERDF criterion for 137Cs by a factor of 4 and for uranium by a factor of 10. Therefore, the radionuclides of greatest interest in this leaching study are first 239Pu, and then 241Am, 137Cs, and uranium. Based on the recommendations of separate engineering studies, four alternative leach treatment methods were tested. The four candidate leachants are nitric acid solutions of Ce(IV), Ag(II)/persulfate, hydrofluoric acid, and hydrochloric acid. The silver/persulfate leachant was tested at room temperature (24?C) and the other leachants at 90?C. Of the four leachants tested, the 6 M HNO3/0.3 M HF leachant clearly gave the best decontamination from TRU, plutonium, americium, and uranium. Under the stated conditions, 89% of the plutonium, 95% of the americium, 90% of the TRU, and 91% of the uranium reported to solution. The leached solids are about 3/2 the ERDF criterion for 239Pu, about 1/10 the ERDF criterion for 241Am, and 1/2 the ERDF criterion for TRU.