On Tue, 29 Nov 2016 19:57:21 -0500, Alex wrote:

The oil will be in solution with the mineral spirits. I am not sure
how you would keep it out. There is no water in mineral spirits. You
really do not need to worry about it just air drying and that will go
pretty quickly if you wipe everything down when you pull it out.

I thought you were suggesting mineral spirits and oil in the ultrasonic
cleaner. How is mineral spirits in firearm finishes?

I was talking about the cleaner but I am not sure about finishes. I
don't think it hurts bluing and the various military finishes but if
you have something exotic, it might be worth googling. Mineral spirits
is on the "oil" side of solvents, unlike hotter solvents like lacquer
thinner. When I was a lot younger I used "gun cleaner" on my old .38
with no ill effects. Then I found out they meant "spray guns" and it
was a hotter version of lacquer thinner. It did clean all of the gum
out of the operating mechanism from some over zealous "greasing" by a
previous owner. When I took the side plate off it was packed with some
gummy kind of stuff.