The stuff my dad used for cleaning down beryllium copper sheets that then had silicon, gold, and nichrome deposited onto them to make tiny medical pressure sensors was generally various stages of xylene, amyl acetate, freon, and - on one notable occasion when a shipment of the sheet stock came heavily contaminated with tractor oil - plain ordinary petrol.

This was back in the 80s.

You are very much Not Allowed To Do That Now.