ASUS rt-ac88u disassembly?

Hi,

I want to open up a second hand rt-ac88u to clean it/replace the thermal paste before I put it into service. Trouble is I can't find any clues on how to get into it. Has anyone opened theirs up? Is the thermal interface paste or a pad? Are the heatsinks even easily removable?

Any input appreciated.

Thanks,
Darren