The ROSE (Resistivity Of Solvent Extract) measurement is a fast and cost-effective method to determine the conductivity of residues on electronic components. Fluxes, such as potassium fluoride, are an important component of solder pastes. However, if they remain on a printed circuit board, their hygroscopic properties can lead to corrosion and thus to malfunctions and failures. To ensure a sufficient quality of the soldered parts, it is thus not necessary to characterize all the ions present separately but to focus on the resistivity of the entire contamination. Therefore, the ionic residues are extracted, either by rinsing or by submersing the sample in a suitable solvent. Depending on the applied test specification, the resistivity of the resulting solution is determined during or after the extraction process. Subsequently, the results are calibrated versus sodium chloride and the results converted to µg NaCl equivalents per cm². The measurements carried out by CleanControlling are based on the common test specifications IPC-TM-650 2.3.25 and IPC-TM-650 2.3.25.1.