This document provides information on contamination and its effects on brakes having carbon-carbon composite friction materials (carbon). Carbon is hygroscopic and porous, and therefore readily absorbs liquids and contaminants. Some of the contaminants can impact intended performance of the brake. This document is intended to raise awareness of the effects of carbon brake contamination and provide information on industry practices for its prevention. Although not addressed in this report, contaminants can cause problems with other landing system components including tires.