Preheat the oven to 350 degrees F (175 degrees C).
Bring a pot of water to a boil; add sweet potatoes and boil until soft, 20 to 30 minutes. Drain, then remove and discard skins.
Mash sweet potatoes in a bowl until no lumps remain; transfer 1 cup to a large bowl, and reserve the rest for another use.
Add sugar, condensed milk, butter, eggs, flour, cinnamon, nutmeg, allspice, and cloves to sweet potatoes in the large bowl. Mix until well combined, then divide batter evenly between pie crusts.
Bake in the preheated oven until firm, about 45 minutes.