After rinsing the plate and wiping off the displaced food, I usually boil a pyrex jug of water so that the steam lifts off the grime. I add a little acid in the form of a squeeze of lemon, splash of vinegar, or some citrus halves. Quick easy, and fairly inexpensive.
But here's my Pointless Gadget of the Month - an Angry Mama, aka Steaming Stella [apologies to all Mamas and Stellas out there- I did not choose the name]
You fill her with water and vinegar, and she will steam clean your microwave oven.
Prices vary from £2 to £10. You can choose other colours, but they are all female.
This gadget is just so wrong from so many points of view!