How to clean out black goo from toilet rim?

I have same problem. I scrub and scrub and scrub. I think it's time for a new toilet with the newer self-cleaning features and special coating surfaces that make toilets easier to clean.

Could need a new flapper,also add 1 cup of vinegar every two weeks

You need a bleach product. My favorite is "Soft Scrub With Bleach." Squirt it up in there and brush it into the holes a little bit. It's thick, so it will stay in place. Let it stand 15-30 minutes. When you come back it will clean off, and the next day your black goo won't come back, at least not as quickly. You should also get a bleach cake to put in the tank. They have different kinds, just read the label. The bleach is what will get in the workings and kill that mold.

i don't like urging stuff in my tank. but you might need to put some vinegar in there or a drop of bleach a few times to clean the pipe between the tank and it coming outta the rim

You can try scraping it down with a pumice stone