I work in company where we machine tungsten shafts, after that we solder two shafts into one pice using silver segments. My question is, how we can remove "fluids pollution" form tungsten shafts (made while we machine them on lathe) before soldering. I am thinking about some kind of acid, digestion, electrochemistry. Any help ?
We we had already tried:
-15 minutes in aqua regia
-30 and 60 minutes in HNO3
(We are waiting for soldering)
I am not a chemist, so sorry for the vocabulary