Liquid anti-oxidants made by mixing specific chemical compositions disclosed herein, followed by thorough stirring so that a homogeneous blend of colloidal-like solutions are obtained. Such liquid anti-oxidants are applied to the surface of the carbon-carbon composite that is needed to be protected against oxidation by brushing, dipping, spraying, or other painting techniques, and allowed sufficient time for the anti-oxidants to penetrate into the subsurface region of the composite and to let dry in a dry atmosphere. The coated carbon/carbon composites can be heat treated (or charred) at a temperature of about approximately 650 to 950° C. for a time period of about approximately one to seven hours. The above painting/heat treating processes can be repeated one to three or more times in order to obtain sufficient anti-oxidant char on or below the surface to a certain depth of the composite.