Machine smells of stale coffee or mold even after cleaning the exterior.

Safety first: Unplug the machine before deep cleaning.

Steps:

• Clean removable parts: Wash the drip tray, used capsule drawer, water tank, and portafilter or capsule holder with hot soapy water.
• Backflush (if applicable): For models with a three-way valve and backflush capability, use a blind filter and espresso machine cleaner to backflush the group head.
• Clean spouts: Use a small brush to clean coffee outlets and internal spouts.
• Dry thoroughly: Allow all parts to dry completely before reassembly.