Sn-based lead-free solders have some characteristics that are different from the conventionally used Sn-Pb eutectic. One is the high dissolution rate of metals and alloys into molten lead-free solder. Several problems due to this high dissolution rate were reviewed. The prominent materials that suffered from this high dissolution rate are copper and iron based. High dissolution rate of Cu resulted in thick Cu-Sn intermetallic compound formation during soldering and Cu enrichment in wave soldering bath. The iron-based materials used for soldering equipments are damaged by erosion. Suppression of the dissolution rate is important to secure quality of micro-soldered joints, to prevent contamination of solder bath and to prolong the life of soldering equipments. The method of suppressing dissolution in practical soldering operation and some examples of erosion damage are introduced.