How to remove enamel paint off Gundam model kits?

I use the de-greaser SuperClean.  It has removed enamels like Testor's, it's not nearly as caustic as oven cleaner (which I used to use), and you can use a batch of the liquid over and over.  It's around $8 a gallon.  Just pour it into a container large enough to hold the piece, submerge the piece, and wait a while.  I usually wait 20 minutes before removing the piece and gently scrubbing with an old toothbrush.  If necessary, I'll submerge the piece again.  Eventually, the liquid will remove all of the paint.

This thread might be better placed in the How-To subforum, for more visibility.

You might want to test any stripper, you plan to use, on a piece of the poly-cap sprue, just to make sure it doesn't damage it.

On the few occasions I've had to strip paint, I've used Easy-Off oven cleaner.  Spray it on, stick the part in a tupperware plastic container (that will never see food again), wait a day then rinse with soapy water.  An old toothbrush will usually get off any residue.