Pop the mango, while still in the container, into the freezer for at least 2 hours.
While the mango is freezing, wash the mason jar and lid thoroughly.
In a small saucepan, over medium-low heat, add ginger preserves and cayenne pepper. Once the preserves begin to boil, turn off the heat and pull saucepan off to the side. Stir in frozen mango and salt. When the chutney is at room temperature, pour it into the jar and cover with a lid. Place in refrigerator.
Chutney will last up to 1 month in refrigerator.