Oven Cleaner or Super Clean.
Simple Green, Pine Sol and other polite strippers generally have a hard time with enamels. You need to call in the professionals to deal with them.
Guarantee that you will be able to see bare plastic within an hour with either of them.
The friendly strippers that are strong enough to deal with spray enamels in a reasonable time period have organic solvents in them which will dissolve the plastic and leave you with a puddle of goo.
So - grab your rubber gloves like June Cleaver used to wear. Snag a bottle of Easy Off. Enjoy the wonders of modern chemistry.
Other independent opinions:
http://www.paintingclinic.com/clinic/guestarticles/removingpaint3.htm
http://www.bonediggers.com/1-3/strip/strip.html