This is a trash can, not an aircraft's engine
https://en.wikipedia.org/wiki/Galvanic_corrosion
Mercury versus aluminum: https://www.youtube.com/watch?v=IrdYueB9pY4
In an earlier life, I shipped items requiring this particular hazmat label on packaging: https://www.safetyemporium.com/12332
Fun fact, if parts are around 30k they can be treated as not worthy of repair. Instead, discard them and nuy a new one.