Is it safe to use a tea kettle with black dots on the bottom? My tea kettle has a bunch of black dots all over the inside bottom part of it.  I tried washing it and using a scrub sponge to scrub it off but it won't come off.  Is it safe to continue using it or am I drinking stuff that's leaching from the kettle?

To better describe this, the black dots are small dots, like if you used a pen to "dot" a piece of paper.  The dots are only on the inside of the kettle, the part that touches the water.  It doesn't show up on the outside bottom of the kettle.  The dots are all over the bottom, there's no one part where it clusters up.

I highly doubt it's mold.  It could be rust but I'd think (but have been wrong many times) it would have scrubbed off with the scrub sponge.  Thanks in advance for your help.

EDIT: Newly attached picture below
Those are mineral deposits. You can remove them with either vinegar or citric acid. Personally, I use citric acid:


Fill the kettle with some water.
Heat the water (doesn't need to boil).
Sprinkle a little citric acid in (use food-grade, also sometimes called "sour salt").
Let it sit for a few minutes.
The spots should vanish.
Dump the water out, rinse it a few times.


Works about the same with distilled vinegar, except you'll want some ventilation when you heat the vinegar (again, not to a boil), as the acetic acid vaporizes.

The heating isn't actually required for either approach, it just speeds the process up.