Peel the potatoes. Cut each potato into 1/2-inch to 1/4-inch slices. Stack these slices and cut into the same width sticks. Repeat with remaining potatoes. Put the cut potatoes in a large bowl, cover with cool water, and soak for at least 20 minutes. Drain the potatoes, arrange them in a single layer and pat them dry with paper towels. Bring oil in a heavy pot. Fry potatoes in a low temperature until the fries are cooked but still as pale. Lift the fries. Drain them on a cooling rack. Let sit until completely cool. Heat the oil add the fries, and cook until golden or starting to turn golden brown. Lift the fries out of the oil. Drain them again on layers of paper towels. Transfer them to a large serving bowl, and sprinkle generously with salt. Serve them.