You've just learned how to open those grilles without losing the clips. Step 1: get new clips ahead of time and have them on hand. Step 2: pull grilles. Step 3: frown upon realizing that you didn't lose a single clip.
Step 4: release frown upon realizing that had you not acquired extra clips ahead of time, you probably would have needed them.
Step 4: release frown upon realizing that had you not acquired extra clips ahead of time, you probably would have needed them.