Set the panel up straight.

Pull the border slightly out and push it forward to release the plastic clips all around the edge.

It's easiest to start at the bottom right or left. You may need the prying tool again for the corner clips.

Be careful not to separate the layers too far as they are still connected at the bottom with fragile ribbon cables.

You'll be able to peek inbetween the layers to blow out dust or insects that got stuck there.

As you can see I had to turn on the monitor in this state to see the dust, but obviously this is not recommended.