Ha ha. I know this. It's actually quite simple. You can't buckle it by hand, it will make a hole in your navel. You can use ear spoons, not those with round heads, or acne pliers, just like small pliers for women to pull out their eyebrows, but with a haircut. When the skin is dry, aim at the dirty things in the navel and gently clip them out, which looks like tearing the skin to death. Be gentle, don't rub it, or you will hurt your stomach at night.