STATION 7. Electropolish Rinse The rinsing of electropolishing solutions is complicated by the fact that the solutions are quite viscous and do not mix readily with water. The speed of rinsing may be increased without increasing water flow by using spray nozzles, counterflows, or multiple rinse tanks. The concentration of heavy metals in the rinse water may exceed the local limits of acceptability. In this case, the system must be arranged to utilize counterflow or backflow rinses which are concentrated in the drag-out tank. This method allows nearly 100% recovery of electrolyte, thereby eliminating the need for extensive waste treatment for heavy metals. The concentrated electropolishing solution may then be returned to Station 5 for re-use or placed in drums for waste treatment as previously described. Care must be taken to avoid drying electropolishing solution onto the parts, as residual acid may cause staining or etching in storage. For this reason, hot rinses must be used only after all residual electrolyte has been thoroughly rinsed away.