Food can get trapped under the blade seal. You'll need to take it apart carefully.
- Unscrew the blade assembly from the cup by turning it counter-clockwise.
- Pull the rubber sealing ring out from the underside of the blade unit.
- Wash the blade, the sealing ring, and the cup in warm, soapy water. You can use a brush to clean under the blades.
- Rinse everything thoroughly.
- Make sure the sealing ring is completely dry before you reassemble it. Push it back into place under the blade unit, then screw the blade back onto the cup tightly by hand.
If that didn't work: If the gunk is really baked on, try soaking the disassembled parts in warm, soapy water for 10-15 minutes to loosen it before scrubbing.
Heads up: Never put the power base in water. Just wipe it with a damp cloth. And never use the blender without the sealing ring properly in place, or it will leak.