The Büchi B-811 Soxhlet extraction system can be used for solid-liquid extraction of solid residues and selective dissolution of metals in volatile organic solvents. The lixiviant evaporates and condenses on the solid material, which is placed in a thimble in the set-up. The extraction system can be used in different modes: Soxhlet Standard, Soxhlet Warm (condensed solvent is heated), Hot Extraction (also known as Randall extraction) and Continuous Flow (continuous extraction with fresh solvent).