How do you know if you can? *Or is that, if you NEED to? Joe pretty much nailed it on the wires..as long as they are in god shape you won't need to. I generally use a cotton ball and denatured alcohol (any alcohol will do) and run it down the length of the cords to any oil and gunk. If they look in decent shape after that you are good.
I haven't had problems cleaning motors with CRC Lectra-motive but it does have a caution about using with plastics. They also have an electronics cleaner that is reputed to me safer.