Hi Gilles!
Generally, we just remove the cable and leave the starter on the engine when I pull the engine out. But if the cable is hard to remove, I would undo the three bolts that hold the starter and remove the starter along with the cable.
On the other hand, if the cable is really that crusty, it may not be "optimal" anymore and you'd be better off making up a new starter cable so all your current draw will be to turn the starter motor, not heat up a crusty old cable
