Your machine is not lacquer it is shellac. If you tested it with acetone it would be sticky. Test it with denatured alcohol and you will see the shellac get soft. What you are removing with the acetone is old yellow oil and may not be covered in brown cig smoke. The acetone can remove old shellac that as turned brown so be careful with the decals with acetone and denatured alcohol. Many of us confuse the brown color as smoke when it is really old oil and shellac. Now I would clean the machine and decals with sewing machine oil and cotton balls or a soft white T-shirt.