It should come of with an eraser.
The shutter goo wasn't too bad, just a couple of spots & sticky shutters.
Got a similar problem (without the stickyness --yet) on a couple of old EOS cameras. How did you go about cleaning the shutter blades? Cotton swab and lighter fluid?.
Pretty much, but I used methylated spirits. You have to be very gentle on the shutters, but you get a feel for it.