Hello YoussefAshraf,
Thanks for choosing the Apple Support Communities. If we understand correctly, you are trying to clean the dust from around your rear facing flash. We can understand why you'd reach out for a solution.
Here is a resource that can help.
How to clean your Apple products - Apple Support
"Apple products are made with a variety of materials, and each material might have specific cleaning requirements. To get started, here are some tips that apply to all products:
- Use only a soft, lint-free cloth. Avoid abrasive cloths, towels, paper towels, or similar items.
- Avoid excessive wiping, which might cause damage.
- Unplug all external power sources, devices, and cables.
- Keep liquids away from the product, unless otherwise noted for specific products.
- Don't get moisture into any openings.
- Don't use aerosol sprays, bleaches, or abrasives.
- Don't spray cleaners directly onto the item."
If you are unable to clean the flash using the methods above, you do have the option to set up an Apple Store or Apple Authorized Service Provider appointment. Please note that service may be limited at this time due to COVID-19.
Apple - Find Locations
Cheers!