Methods of reducing an initial cross-sectional area of a hole in a component to a predetermined cross-sectional area including preparing a composition comprising at least an aluminum alloy with a melting temperature higher than aluminum, applying the composition to an interior surface of the hole, and then heating the component to cause a metal within the component to diffuse from the component into the composition and react with the aluminum alloy in the composition to form a coating on the interior surface of the hole. The heating step is performed to selectively modify the initial cross-sectional area of the hole and thereby directly attain the predetermined cross-sectional area thereof.