Using fuel system cleaner is certainly less work than the way I do it.
I have done this.
-Remove the smoke unit from the loco.
-Remove the bottom cover from the smoke unit.
-Submerge the smoke unit on its side in acetone for several hours.
-Dry it off overnight and assemble/reinstall it.
This technique works for the ones I have done. You can see the acetone turn yellow as it dissolves the old smoke fluid.
I'm dubious that the pure mineral oil trick will work because smoke fluid is basically mineral oil anyway.
