Hi, I have pcbs (Duroid/RT 5880) with raw copper, soldered in vapour-phase chamber at 230 degrees Celsius. During soldering, copper gets tarnished. Cleaning with Vigon A250 removes the tarnished layer. Indeed, in the VigonA250 techn. datasheet it is reported that the clean agent attacks copper. Do I have to worry for this Copper attack? how properties of copper surface are affected? thanks.