I absolutely can't stand my engine bay being a grease pit. I decided to borrow a parts cleaner from a friend and bought some quality cleaning solvent ($35) to use on a few parts that Simple Green just couldn't work on. My goal was to get everything looking like it came back from the factory.
After a few minutes with working on a hip high table, I learned that the cleaner should be closer to me so that my neck and back wouldn't start to ache from bending over. I would recommend putting it on a table and sitting down in a chair. I however propped the cleaner on a 5 gallon bucket and sat on another bucket. Some people might get naucious from the fumes (it smells like gasoline a bit), so make sure the area is ventilated. You might need to use a respirator if it makes you sick. I'd also recommend using eye protection and a pair of latex gloves. Get yourself a toothbrush and a wire brush and begin.
I started by filling the cleaner with the solvent, so that the solvent was filled over the pump's inlet. I generally let the part soak in the cleaner for a few minutes before scrubing with brushes. The wire brush works very well with getting grease and grim that is really caked on the part. The toothbrush was used more for nooks and crannies that the wire brush couldn't get to. If there was grim in a crack that the toothbrush couldn't get, I put the nozzle on the spot and turned the pump on, leaving it for a few minutes. I then came back and use the toothbrush. This method worked quite well. Be careful with parts that contain rubber within them. After 10 minutes in the solvent, the O-ring on my coolant pipe noticeably expanded. After two hours it came completely off (I was getting new O-rings anyway and wanted to see the outcome).
It took me about 2 hours to clean my power steering pump, alternator, oil filter housing, coolant pipe, and a few brackets. I was very happy with the outcome. The solvent worked much better than Simple Green, however the part needed to soak in the solvent for a few minutes to start to break down the grease. The alternator didn't turn out so well, possibly because it's so close to the road and sees quite a bit of filth but it did turn out much better than what it started like.
Use an air compressor to blow the part off and to get trapped solvent out/off of the part. Set the part aside to dry off. Make sure to wash your hands very well after, even if you were using latex gloves. Dispose of the solvent the proper way.
