According to :
Most of it washed off with water and scrubbing, but there's still a
red stain all over inside that wouldn't come off with gunk or lacquer
thinner. This is definitely not rust.

Is there anything in make-up that can harm concrete?

Not at those quantities.

No, I wasn't making out with the mixer. This thing came from a
cosmetics factory and then sat unused in a warehouse for several
years.

That's right, ladies - your make-up is made in concrete mixers!

The alternate is a Hobart (restaurant duty mixer), and those
things are _expensive_.

[High power model rocket motor and fireworks manufacturers use Hobarts
to mix large batches of propellants.]

You could always put in a couple shovels of sand, some water to make
it a thickish slurry and run the machine for a while. That'll
sand most of the rest off.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.