Now that you've landed on your feet with the stains, you might want to ask why there was black grease in there in the first place. DS and I took my Viking apart recently because the shop where I bought it wouldn't let me watch while it was being cleaned. It was full of thick, black grease. "Where is all the lint," I asked naively, and there it was, embedded in the grease, making it like putty. DS removed every bit and substituted a clear lubricant that he felt was more appropriate to the plastic gears. Can't remember the name but could find out.
Now, I suppose that catching lint might have been part of its purpose, but I was glad to get it out of there.
Hugs,
Charlotte