If you don't know How To Clean Iphone Speakers (https://techzeel.net/how-to-clean-iphone-speaker/) then below are some of the ways:-
1. The first thing that you can do is brush it gently with the help of a soft-bristled toothbrush.
2. You can also use air compression for deep cleaning.
3. A small piece of adhesive putty or painter's tape is also very useful for cleaning iPhone speakers.
4. You can use a dry microfiber cloth also.
5. You can also play a low-frequency tone in your iPhone.