A loose coin can move beyond an obvious pocket or door fold. If it is visible and safely accessible after the programme, retrieve it without probing the machine.
Understanding this situation
A repeated metallic sound or a missing coin does not identify a precise internal location. Removing panels, reaching around a moving drum or inserting tools through drum perforations can cause injury and damage.
A useful next step
Stop further use if the coin is accompanied by abnormal noise, snagging or a drainage problem. Tell the repair team when it entered and what changed. Check pockets in future loads rather than using the filter as a routine catch-all for known loose objects.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.