I am not sure about Jenn-Air vs. Amana or Kenmore, but I know that the pans on my refrigerators seem to pull right out to empty. I would think that this would be the case with yours, as well.
In mine, just pull up on the plastic and out towards you and that should do it.
Or if it won't come out, try a wet/dry vacuum cleaner after removing the front grill if there is one.
I searched the FAQ's for this but Jenn-Air didn't have that.
They do have a chat section, though, under customer service:
http://www.jennair.com/flash.cmd?/#/page/customerservice/