I have a Dometic RM3962RSSFX dual power fridge/freezer. The unit is clean, but there is an awful mildew smell, especially in the freezer. Wiping down with bleach water and airing out for several days hasn’t helped much. Any idea what those screws/washers are in the back of the freezer? The screws are rusty and I’m wondering if I can remove/replace them.