We had a customer who was doing stamping of lead frames for components. They had a similar problem with soldering To make a long story short, they are now using Cooks oil as the stamping oil, and cleaning with an Axarel 2200 process. Ion chromatography showed the items to be clean. Your customer might give the Cooks/Axarel combination a shot. They used Axarel as the alternative to their standard trike process. Doug Pauls CSL [log in to unmask]