Soldering without using liquid fluxes is standard practice for the assembly of electronic, optical and mechanical components as the chemicals and their residues can adversely affect the performance of sensitive components. Chemical fluxing includes removing oxide films from metal surfaces, which otherwise impede spreading and humidification. This is essential for successful soldering and joint formation. Fluxless soldering processes use alternative methods to achieve the same goal. In fluxless soldering oxide films are removed by reduction, displacement or dissolution.