This is a special kind of ugly. Maybe it's my water, maybe it's
something else particular to me, but it happens with any brush I use for
cleaning in the sink. And it does not take long.

https://www.flickr.com/photos/27532210@N04/?
If you have any trouble viewing that, I can make it easier to see.

The first picture should be my Black & Decker battery-powered spinning
scrubber attachment.

What is that orange brownish crud? We have hard water but it's not lime,
it does not come off after days of soaking in vinegar. I just tried
soaking it in some heavy duty cleaner-degreaser "Purple Power" and that
didn't work.

So how do you get it off?

Thanks.