Our microwave ovens do more than their share of heating and cooking. This results in splats and splatters on the interior. If left on too long they are difficult to remove. Clean yours in a jiffy by filling a bowl with water, add a few lemon slices to it, and heat for 5 minutes. The steam will have loosened the gunk from the walls so they’ll wipe off easily. The lemon has disinfected so you’re good to go!