Put the mango slices in a large bowl and sprinkle with salt.
Leave overnight.
In the morning drain off the juice and rinse the fruit.
Put the garlic, sugar, apples, mustard, ginger, vinegar and cayenne pepper in a pan.
Now heat over a low heat to dissolve the sugar and then bring up to the boil.
Add the mangoes and simmer for 30 minutes until the chutney is thick and syrupy.
Turn into sterilised jars cool and seal.