jim rozen wrote:

I use the 5wt ATF in a glass hypodermic syringe to lube
those machines. It's a great way to get that 'just one
drop' that's required in some spots. Plastic syringes
degrade and the plungers lock up on them after a while
being exposed to ATF though.

Mineral oil, as sold in pharmacies, is water clear and a good lube.
There are two grades, light for body rubs, and heavy, for a laxative. I
found mixing them 50:50 gives a nice viscosity for a quenching oil while
the light (in a plastic syringe) is a good light instrument oil. If you
want a corrosion inhibiter additive as well then try CRC 3-36.

Ted