How do I get the inner part of a crockpot unstuck?

I used a small crock-pot I had for the first time a couple of weeks ago to cook little smokies for a holiday party I threw. Before I started cooking, I took the inner "pot" out of the crock-pot and rinsed it out. However, now the inner pot is completely stuck to the outer pot. Does anyone know what might have caused this, and how I can fix it?