Diagnosis
Food residue and liquid are trapped under the blade assembly's retaining ring and seal, a common issue with regular use.
How to Fix It
Use the official disassembly tool (part #BDO-T) to unlock the blade retainer ring. Turn counter-clockwise. Remove the ring, blade, and seal. Soak all parts in warm, soapy water. Scrub the groove in the jar base with a small brush.
If That Didn't Work
For persistent odors, soak the disassembled parts in a solution of 1 teaspoon citric acid or white vinegar per cup of warm water for 15 minutes. Rinse thoroughly.
Heads Up
Never submerge the entire jar base in water or put it in a dishwasher. Only the disassembled jar body, lid, blade, ring, and seal are top-rack dishwasher safe.