• Holding mechanical parts together during assembly, for example some parts in automatic transmissions. It dissolves in the transmission fluid and doesn’t impair it’s performance or clog anything like greases could.
• Packing a replacement oil-pump with it to effectively pre-prime it so it pumps oil as soon as you start the engine it’s attached to.

Industrial-scale coffee brewing can use counter-flow heat exchangers to recover pretty much all the heat energy, combined with insulation to prevent losses.