Way back in the late 1960's I worked in a factory that repaired all sorts of electrical motors.
We used to take them apart then clean all the metal housings etc in a paraffin vat.
I was cleaning 1 when the paraffin gun stopped working, without thinking I turned the gun to look and see if the nozzle was blocked and guess what yup it started again.Ended up at local hospital having my eyes washed out.