When you burn it, sugar turns black and hard, leaving nasty, dark stains in your pot. Placing the pot in a dishwasher usually won't remove the burned sugar and may make it harder to remove. Treat sugar stains in pots as quickly as possible to reduce the chances of permanent stains.
Fill the pot half full of white vinegar.
Place the pot on the stove and bring the vinegar to a boil. Once it starts boiling, allow it to continue for 5 minutes.
Pour out the vinegar and place the pot in a sink of hot, soapy water.
Sprinkle some baking soda onto a nylon scrubbing pad and scrub off the burned sugar.
Rinse the pot and dry it before storing it.