Focus LV Tail Lights has Turned Yellowish, How to reach inside?

[RadioactiveX]

The clear tail lights on my lv (the inner plastic) has turned yellowish. I've seen this is common with mk2.5 Focii when I look around in town. Does anybody know how can we reach that inside clear plastic (the one with the honeycomb pattern) so I can polish both sides with a headlight restorer kit?

Thanks heaps,

RadioactiveX