My mom used to do this to her pots every night. If you want to try to save it:
1. Soak pot with dishwasher powdered (or whatever) soap in it overnight, scrubbing in the morning. You probably could scrub with baking soda, it won’t scratch.
2. Sometimes she would soak again all day and all night, scrubbing at each end of the day. She’d do this maybe for a couple of days, depending on when she needed the pot again (she wasn’t much of a cook, and worked all day).
3. If that doesn’t work, then you put some water in the pot, a little dish soap AND a little dishwasher soap in the pan then heat it on medium on the stove for a while, then scrub it.
Sometimes this process would take a few days, but she never threw a pot out.
Also Barkeepers Friend might help. It doesn’t scratch either.
thumbstumbler 
My mom used to do this to her pots every night. If you want to try to save it:
1. Soak pot with dishwasher powdered (or whatever) soap in it overnight, scrubbing in the morning. You probably could scrub with baking soda, it won’t scratch.
2. Sometimes she would soak again all day and all night, scrubbing at each end of the day. She’d do this maybe for a couple of days, depending on when she needed the pot again (she wasn’t much of a cook, and worked all day).
3. If that doesn’t work, then you put some water in the pot, a little dish soap AND a little dishwasher soap in the pan then heat it on medium on the stove for a while, then scrub it.
Sometimes this process would take a few days, but she never threw a pot out.
Also Barkeepers Friend might help. It doesn’t scratch either.
I soaked this pot out without having to do all the steps above. I bet yours might come clean too
http://mostlygranola.blogspot.com/2011/12/now-thats-how-to-properly-burn-pan.html