I would not recomend steam cleaning as this can have a damaging effect on all plastics and hoses. I agree with what most people have said, I usually take a few plastic bags and cover the plugs and computer and spray dont with either simple green or other degreaser and have at it.
Like the person above said, be sure to degrease the hood and clean it as well. It also doenst hurt if your spending the time to use a cleaner afterwards and even a wax. I have done this to my TEG and it has helped me to keep it clean and able to wipe the dirt off easier now.