There's a black substance leaking out of my Ooni Fyra 12.

If you're seeing a black, oily substance coming from your hopper and/or chimney, don't worry. This is creosote, and it's very easy to remove.

What causes creosote?

1. Incomplete combustion due to a smoldering fire.
2. Incomplete combustion due to moist or wet pellets.
3. Restricted airflow. 

How can I prevent creosote?

• Make sure the flames are rolling before you top up pellets.
• Store your pellets in an airtight container or sealed bag to prevent any moisture from getting in.
• Make sure the chimney cap is off, the chimney baffle is open, and the door is on while cooking.

How can I clean off creosote?

1. Using a towel or non-abrasive sponge, wipe your oven down with soapy water.
2. For more stubborn marks, use Bar Keepers Friend (see image below) or Weiman’s Stainless Steel Cleaner and Polish. (only use this on the stainless steel in your oven.)
3. Dry your oven thoroughly before the next use.