PCB flux residue

[ppppenguin]

That must have been a few years ago. Carbon Tet was more or les banned as a carcinogen a long time ago. In the late 1970s, early 1980s my employer used 1:1:1 trichloroethane, aka "Trike" for washing PCBs. Now banned under the Montreal Protocols. I believe all modern production line cleaning is water based. Cheaper and cleaner.

IPA (isopropanol, propan-2-ol, isopropyl alchohol) works pretty well and is readily available.