Diagnosis
Yeah, this one's common. The door is double-paned glass, and over time, grease and steam can seep into the sealed gap through microscopic openings, especially around the edges.
How to Fix It
There's no safe way to take the door apart without risking breakage or ruining the seal. The official method is prevention and exterior cleaning. For the interior glass surfaces you *can* reach, use a non-abrasive oven cleaner spray, let it sit, then wipe. For the sealed gap, you're stuck.
If That Didn't Work
Some owners have had limited success by carefully using a thin, flat tool wrapped in a microfiber cloth dampened with vinegar or degreaser to *gently* work along the very edge of the inner glass seal, but you risk pushing more gunk in or damaging the gasket.
Heads Up
Never submerge the door or get excessive liquid near its edges or hinges. That can force more moisture into the glass panels and damage the electronic door switch. It's a design flaw you mostly have to live with.