A removable shelf or trim may not be seated fully in its supports. Check the owner assembly diagram with the shelf unloaded rather than wedging it tight.
What the observation tells you
A small gap can let a fitting vibrate during ordinary operation. Paper, foam or adhesive inserted as a wedge can interfere with cleaning, airflow or secure support. A chipped shelf edge or cracked support needs a different response from simple incorrect seating.
A useful next step
Refit only permitted removable parts as instructed. If the fitting remains loose or damaged, stop loading it and ask about a correct replacement. Note that the sound began after cleaning.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.