I've used the Bug and Tar remover on all of my machines from the plastic to the old iron ladies and it works very well. It says it will not remove wax and is made for clear coats, apparently shellac is not included...
As far as fumes the smell isn't bad but I have to wear a paint mask when using it or it wreaks havoc on my sinuses and I get a bad headache.
Best used outdoors or with a workbench exhaust system if you are sensitive