The methods that happened to work out for others may not be best choice for you. Depending on what your particular case is made of (and especially the paint used) you'll want to start with the least harsh methods first and gradually work your way up as far as necessary.
Instead of starting out with harsh chemicals that may possibly melt your plastic case or possibly damage a metal rack cases paint, you might consider sanding it off with some extra fine (furniture re-finishing grade) steel wool first.
(I've seen regular old WD-40 remove all kinds of stuff without damaging the surface too)
There's lots of ways to get paint off, but If your concerned about damaging the underlying surface, try all methods/products on a small spot first (like somewhere on the racks bottom side) so ya know for sure if its going to damage the cases surface or not.
Here's lots more paint removing info for ya:
http://www.google.com/search?sourcei...ng+spray+paint
Good luck.
