I had my wood stove guys out last week to replace my 2017 Jotul F500 under warranty, less than a year old, with enamel flaking on one side panel. I'd brush cleaned the flue the day before they arrived and wondered where the ashes went. They showed me two 10mm nuts that hold the top oval plate in place at 12 and 6 o'clock. They are hard to reach above the secondary burners. They just need to be loosened, not removed, to allow the metal clips to twist and rotate 90 degrees. The clips fit within two raised nipples on the main casting. The oval top can then be lifted off to gain access to the back flue. Then a small flexible vac hose can suck out ashes from the back flue area. There's a white heat blanket that can be gently folded and removed after gaining access to the top of the stove and shaken clean. A vac can damage it. Hope this helps someone.