Our Carousel R209KK has been in storage for the last 3 years and wasn't used prior to that. When we went to use it just now, we noticed there was a paper-ish, manila-colored panel on the interior left wall of the microwave. The edges are tucked into slots to be held in place. Should this be removed prior to using the microwave or does it stay put? The photo shows what I am referring to. Thanks! Elizabeth :)