The black slime on your faucet looks nasty, but it's a buildup of oxidized manganese and (harmless) bacteria. Here's how to clean things up.
bathroom - What is this black stuff that appeared on my drain after cleaning with a bleach-based cleaner and how do I clean it? - Home Improvement Stack Exchange
How To Remove Calcium From Faucet, Hard Water Stain Removal, Easy
Signs That You Have Mold in Your Water Pipes
How to Fix a Leaky Faucet: Guides for Every Design and Style
The Dangers of Drinking Moldy Water That Is Hiding in Your Sink
Black Slime On Faucets: What it Is and How to Get Rid of It
Bacteria, mold and household water
Best Bathroom Materials When You Have Hard Water
Home & Living Taste of Home
Did you know you should routinely deep clean your sink faucet aerator?, faucet
If You See Green Residue in Your Sink, This Is What It Means
Why Does My Water Have Black Specks in It?
How To Fix Black Water Coming Out Of Faucet - Heartland Inspections
5 Powerful & Proven Tips to Prevent Faucet Corrosion - NIR Plumbing