In a large bowl stir together warm water and salt until dissolved. Add potatoes and cabbage leaves. Cover with plastic wrap and store in a cool place for 4-6 days (not the fridge, but a basement or pantry works well).
When ready to fry fries, drain fries and heat oil to 325 °F. Fry potatoes in batches for five minutes until fries are cooked through, but they won’t get crispy during this fry stage. Remove fries and let drain on a large baking sheet lined with paper towels.
When all fries are fried, turn heat up to 375 °F. Re-fry fries, in batches, for 2-3 minutes until fries are very crispy.
Drain fries and serve with ketchup or other dips. They shouldn’t need any extra seasoning.