Doug White wrote:

I've been very happy with it as well. It works as described, and I've
never had it attack anything. If you can't compeltely cover
something & leave it in for a long time, you can get discoloration at the
air interface, but I've never had any corrosion or pitting.

It does remove some paints.
The blue paint on an old AA minilathe doesn't hold up to it, but it's
probably the cheapest water-soluble stuff available in the 1930s. Seems
more akin to whitewash.

At the other end of the scale, it attacked the paint of an Emco 8.6
tailstock, which really surprised me. But I did emerse the entire
tailstock, with good results. And the Evaporust was very black when I
put it in. That particular gallon left with the new owner of the lathe.

One trick I learned for large objects is to soak a piece of synthetic
chamois cloth ("super towels"), or a sponge in it, and then lash it to
the rusted surface for a while. I've managed to remove a lot of rust
thsi way from a sheet metal shear that I don't want to disassemble.

Another option for large objects that are not readily submersible:
Get a tabletop fountain pump from HD or a craft store. Pump the fluid
over the rusted area so that it runs back down into your tub of
Evaporust, where the pump is submerged. It washes the rust off.