would love to know how to remove the dust inside my LCD panel

The Dust problem!

If you had an older 2011 iMac the cover glass is easy to get off, and has a space that is not closed off it and can get dusty. The newer 2012 onward are technically sealed! The open cell foam apple uses does allow a bit of air flow (to adjust for air pressure) but it’s not porous enough to allow dust through.

So what is going on here this looks like dust! What you are likely seeing is the degrading of the liquid crystal material, over time and the amount of static twist the liquid crystal has endured the screen can appear as dusty!

Just like an elastic can lose its spring so can the liquid crystal material and being forced at a set pull likewise can lose its ability to return to the neutral state.

So what to do? There are some apps you can run which exercises the liquid crystal so it can return some of its flex. Otherwise there is nothing you can do to fix this once its become an issue.

OK, is there any way to prevent it? Yes! surprisingly its not using a photo as a background image instead use a solid mid tone color. Also don’t run your display at high brightness.