Wash the limes thoroughly and cut them into wedges.
Add the lime wedges to a blender.
Pour in the cold water.
Add the sweetened condensed milk to the blender.
Blend on high speed for about 30 seconds until well combined.
Strain the mixture through a fine-mesh sieve into a pitcher.
Press the lime wedges to extract all the juice.
Stir the lemonade well to combine.
Serve over ice in glasses.
Garnish with lime slices and fresh mint leaves.