Normal soaps are comodogenic and can actually overdry the skin, promoting excess oil production.
All I know is, this worked for me - I eliminated, almost entirely, the following;
touching my face
stress
wheat/gluten products
dairy products
sugars
I increased whole grain foods, veggies, fruits, etc, worked out like a mofo 3 days a week, and had 2 showers a day instead of one. Now for someone that went from having quite bad acne and ridiculously greasy skin to being completely clear and much less greasy skin, it was amazing. You obviously wouldnt/shouldn't have to do all of that though...
Also you can use these rice paper sheets - they don't irritate the skin and you can dab your face etc with them as needed.