Too bad you have such a small area. PB Blaster is my weapon of choice for the really bad ones. It does stink to high heaven though.
I have a 31-15 head that kept dripping black gunk. I had finally had enough and took it to a do it yourself car wash. I washed it out with soap and water under light pressure then rinsed it really well - 3.00 worth of quarters - but it worked! I let it drip dry then gave it a light oiling. No more black gunk dripping from it, in fact it is sitting on the floor with nothing under it to catch drips. If the decals are shot on the 127 the car wash might be something to consider.