I've used both Fantastik and something called Resolution degreaser. Both have worked pretty well. I found that it's best to try to use a light mist and enough to wet the surface, but not enough to run. If they sit on the gunk for a couple of minutes, the gunk wipes right off. But, to tell the truth, I'm done cleaning the window. It's getting too cold here. Either the window gets too cold, or if it's warm, I get too cold trying to clean it.
The racks and other removable internal stuff is another matter. I've found that a little Dawn and Oxi-clean, hot water, and a 45 minute soak in a properly sized storage tote (why yes, that was me in the storage aisle with the measuring tape) will allow the gunk and stains to wipe or rinse right off.
Ron