The galvanizing reaction will only occur on a chemically clean surface. Most preparation work is done with this in mind. Like most coating processes the secret to achieving a good quality coating lies in the preparation of the surface. It is essential that this is free of grease, dirt and scale before galvanizing. Contamination is removed by a variety of processes. Common practice is to degrease using an alkaline or acidic degreasing solution into which the component is dipped. The article is then rinsed and then dipped in hydrochloric acid at ambient temperature to remove rust and mill scale. Welding slag, paint and heavy grease will not be removed by these cleaning steps and should be removed before the work is sent to the galvanizer. After further rinsing, the components will then commonly undergo a fluxing procedure. This is normally applied by dipping in a flux solution - usually about 30% zinc ammonium chloride at around 65-80°C.