Welcome to the Quilting Board!
the last pile of melted gunk I had, came off with bug and tar remover. I didn't use that all the way down to the metal, but putting cotton balls saturated on top loosened a lot. I had nothing to lose on that machine. I did coat the metalwork I wanted to protect with oil before positioning the cotton ball, and didn't lose any paint.
I'm a Queen.... at least my pantyhose say I am!
(proud caretaker of a magenta 221, purple 222, assorted 66's, a 301, a pink Atlas and Monarch, and Granny's 201-2.
What I used on the Pfaff 130 in the pictures was Rubbing Alcohol 91%. The before picture shows a lot of black gunk, a small pile, and it came off with Rubbing Alcohol on paper towels. Wipe it off quick though.
I bought a Singer 15-30 treadle with gingerbread/ tiffany decals years ago that had an added on motor with 'melted' wiring. The melting was so bad that it had run over the up-right arm, over the bed and down onto the wooden belly pan. Funny how older wiring either melts into a goo or becomes totally brittle.
I removed it with kerosene. I soaked small flannel rags in kerosene. I then placed the rags on a small section of the wiring puddle for 10 minutes or so then rubbed the puddle with this rag. I continued to repeat this using a fresh rag each time. This action slowly removed the puddle a tiny layer at a time. Nothing quick about job. A small amount of the goo never came off of the belly pan.
This machine is now drop dead gorgeous. I had no damage at all to the decals, but the shellac on this machine was intact. If the shellac had been compromised I suspect that I would have seen decal damage.
"Most sewing machine problems are due to the carbon based unit in the chair in front of the machine"
I have some work to do on a couple melted up machines. I'm going to try all of the above and see what gets the goo off. Just not today.
NEVER LET A SEWING MACHINE
KNOW YOU ARE IN A HURRY
Well if all else fails you could soak it in kerosene and light it. That should "melt" the gunk off. LOL.