Leftover bread doesn't have to be made into bread crumbs. Yesterday's muffins, bagels or walnut-cranberry semolina loaf can all be revived easily. Bread that is rock hard, though, cannot be saved by this method.
Preheat oven to 325°F (165°C).
Place the stale bread in a clean paper bag. Fold or twist the bag's opening to close.
Dampen the bag lightly and evenly with cold water. The surface of the bread may become a little wet, but avoid soaking the bread's interior.
Heat the entire bag in the oven until the bread is softened and warmed through. Sprinkle with more water if the bag dries before the bread is ready. Allow about 5 minutes for rolls or slices and at least 20 minutes for large loaves.
Be sure to remove the bag from the oven before it scorches or before you increase the temperature.
This is also a good way to defrost and heat frozen breads in one step. Lower the oven temperature to 275°F (135°C) for baked goods taken directly from the freezer.