A method includes forming a ceramic matrix composite component by infiltrating an array of ceramic-based fibers with a ceramic-based matrix; forming a plurality of cooling holes in the ceramic matrix composite component; applying a slurry of particles in a carrier fluid to the ceramic matrix composite component such that the slurry passes through the cooling holes and wicks into the ceramic matrix composite material; and processing the ceramic matrix composite component to remove the carrier fluid, thereby leaving a filler at a wall surface of the plurality of cooling holes. A component is also disclosed.