A good degreaser, but not so tender on plastics.
In the old days, I'd just use some carbon tet.
Argh, I was wrong. Perchloroethylene is allowed here and used for dry
cleaning, although there is a bill to ban it from the opposition in the
Swedish Parliament. Trichloroethylene OTOH has been banned since the
90s. *That* smells nice too ;-)
There used to be a washing device for car parts at Volvo which used hot
trichloroethylene which you sprayed on the part to be cleaned. Amazing
how fast it removed all traces of grease, underseal etc from a part from
the front suspension of my parents' Volvo 544... The sand blasting
thingy alongside took care of all the rust in short order.
/Jonas