I use a soft bristled tooth brush

Or you can use a microfiber cloth

Me too…works the best. I do it once every week…

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Also works great for around the camera lenses

Compressed air

I use a keyboard brush. Soft and thin.

Loud music always emits a puff of talc from mine.

No man. The air pressure (if you press it all the way )might damage the membrane.

Same here but with a drop of alcohol. I also turn iPhone so that any dirt or dust falls down when brushing. Don’t lay in such way so that grime falls (back) in.
Although it’s debatable, does anything falls down when you’re cleaning that way because you might be pushing it back into it; better to be safe than sorry you might position the iPhone as I mentioned before

I use scotch tape (or packing tape). Not intrusive and picks up all the dust and debris. I kind of kink it in there with my fingernail, ensuring I don’t push too hard or damage anything. I don’t like using a brush or air or anything like that since it’s pushing all of the gunk back into the device.

For the camera lens and around it (where dust and dirt likes to settle), I use a clean a-tip. Works wonders.

Take a toothpick to it and go to town.

If you have a Apple Store nearby, you could ask them to clean your phone

I’ve genetly used blue tac and lightly pressed it on the speaker

Be very careful with a tooth pick, the gauze covering the speaker repels water not sure that’s the right word. I’m sure even a tooth pick could damage it. I use blue tac