Accurate measurements of rhenium (Re) and sulfur (S) concentrations in solid samples are of critical importance for the key research activities at the Pacific Northwest National Laboratory (PNNL) Waste Form Development Laboratory (WFDL) related to Re behavior during waste glass melting process and solubility of S in glass. Southwest Research Institute (SwRI) has provided reliable services for chemical analysis needs at WFDL; however, its long turnaround time, occasionally up to 5 months, has caused some difficulties. An in-house method was developed for dissolving and fusing glass and feed samples in preparation for analyses by inductively coupled plasma-optical emission spectrometry and -mass spectrometry at a PNNL facility.