I was chatting with two coworkers tonight...both of them experienced ex-military and gun nuts. They recommend scrubbing with WD-40 until the piece is clean, then a thorough and careful oiling. FWIW.
WD 40 is one of the most overated products in history. Kerosene in a can.
I worked for years in a machine shop. We cleaned everything with varsol and brake cleaner. Guess what, they are both very bad for you. When I clean parts now it's with hot water and dish soap. Use a nylon brush and get busy. I think the simple Green plan is a good one. Carb cleaner has toluene and Benzine in it. Both accumulate in your system and cause long term liver damage. They are carcinogens. Avoid if at all possible.
There is nothing wrong with using water if you air dry and oil immediately after. And yes nothing cleans quite like petroleum based products.