The clumps and clods fall off easily enough each time the decoys are stacked or bagged, but there remains a mud-based patina that clouds the lifelike patterns and colors. At the very least, separate your decoys and hose them off. If they've gone more than two seasons without a bath, gather all the neighborhood kids, issue buckets and sponges, and send someone for an economy pack of those single-serving Blue Bell ice creams. While the goose decoys are all over the yard, try to match up bodies with heads. I can almost guarantee that you'll be missing some heads.
Replacements are cheap.
Buy extras, so you can get through this season without having to look every morning at that annoying stack of headless decoys. The squares of plastic banquet cloth that make up the bodies actually hold up fairly well, but not so the wooden dowels that support them. Sticks that spend most mornings stuck in wet mud don't last forever. Many don't last a full season. If you're really tight on money, minor cracks can be repaired with a couple of turns of white or black duct tape.