This happened to me once before, only much worse but I was so frantic about getting it fixed that I never took any pictures. This time I was much more relaxed, even though it occurred in the middle of my cooking, so I took pictures.
I was making chili and also catching up on watching "How to Get Away with Murder." I guess I got really engrossed in the show and when I got up to stir the chili (I hadn't but in the tomatoes or beans yet) it was all burnt on the bottom. I quickly shut off the stove and transferred what I had so far into a bowl. I then looked up how to clean the pot since I didn't remember and I didn't document it the last time. Below is what my pot looked like to start. All that you see was firmly stuck to the pot.
I added 1 cup of vinegar and 1 cup of water. Since this was enough to cover all the burnt stuff I didn't need to add more water which you could be added if needed. Then I let it come to a good rolling boil. Once it came to a boil I added 3 tablespoons of baking soda and it fizzled away.
Next I poured off everything that was in the pot and scrubbed lightly with the abrasive side of a sponge. Below is the mid scrubbing picture. It came off so easily.
Note; 12/15/15 - while I was looking at something else I saw that I did post this before right here.