I just found this great forum while doing a search for information about the black gunk on one of my bathroom sink plugs. I used to have bathroom sink plugs that could be unscrewed, but these are the kind that have to be unscrewed from below the sink, and right now one of my hips won't let me get down on my knees. (I had the other hip replaced very successfully a llittle more than a year ago, and will have the remaining original hip replaced soon.)
I really was looking for a name for this black gunk - but I think I know where to find that. I did find some very interesting tips to others who needed help on how to clean out clogged drains. Been there, done that.
Now that I live in a condo, my do it yourself tasks are somewhat changed from living in a house. So I am having to learn some new things. I am going to try to find some answers here and sure that I will. This looks like a great bunch of people.