I use crushed walnut shells and I deprime first. I inspect each case after cleaning anyway and remove any media in the flash hole. I made a tool for that. I took a screwdriver and ground both edges to form a point in the middle small enough to fit the flash hole and ground the remainder of the head so it will fit into the primer pocket. This way I can clean the primer pocket and clear the flash hole at the same time.
But this is the first time I heard of putting some patches in the media. I'm going to have to try that trick.