Diagnosis
Food particles are trapped in the bearing seal. This is a design challenge with all removable blade assemblies.
How to Fix It
Fill the container halfway with warm water and a drop of dish soap. Secure the lid. Run the blender on high for 30-60 seconds. Rinse. For stubborn bits, use a long-handled brush through the fill cap opening to scrub the underside of the blades.
If That Didn't Work
You may need to disassemble the blade. The blade assembly on the ONE is not user-serviceable. If residue causes a leak or odor, you must replace the entire container.
Heads Up
Never immerse the base or try to pry off the blade assembly from the container. You will break the seal and void the warranty. Clean immediately after use.