The CLEAN indicator light stays on or flashes and the coffee maker beeps, sometimes refusing to start a normal brew.

Safety first: Allow the unit to cool before handling. Unplug when not actively running a cycle.

Run a full cleaning cycle:

• Fill the water reservoir with a 1:1 mixture of white vinegar and water up to the MAX line.
• Place an empty carafe on the warming plate and ensure the filter basket is empty.
• Press and hold the CLEAN button (or follow your Oster model's instructions) to start the cleaning cycle. The cycle may take 30–45 minutes and will pause intermittently.
• Once complete, discard the solution and run 2–3 full reservoirs of fresh water through the machine to rinse.

Reset the CLEAN light:

• On many Oster models, the CLEAN light will turn off automatically after a full cleaning cycle.
• If it remains on, unplug the unit for 5 minutes, then plug back in. Some models require holding the CLEAN button for several seconds to reset.

If the CLEAN light returns quickly after descaling, there may be heavy internal scale or a partially blocked heating tube that requires repeated descaling or professional service.