The residue that appears during cleaning may be loosened deposits, but the black color does not prove that it is mold. Gather what is visible and check whether the material is decreasing or seems to be coming from a damaged part.
Observe the residue without assigning a cause based on its color
With the machine empty, stopped, and cold, check what remains in the drum and along the edge. A soft film, a clump of soap, and an elastic fragment are not equivalent observations. You do not need to dissolve them to describe them; record appearance, amount, and when they first appeared.
If there are fragments that look like rubber, metal, or plastic, inspect only the visible parts. A new noise, rubbing, or leak changes the priority: avoid more cycles until you determine whether there is wear or damage.
What to do after a cleaning that releases deposits
- Remove any accessible residue with a soft cloth or the method in the manual, without pushing it through the perforations.
- Check the authorized surfaces and collectors where it may have built up.
- Complete the rinse cycle planned for the treatment. If the manufacturer advises repeating the cleaning, follow that specific instruction.
- Look at the empty machine again and compare the amount. Do not put in clothes to catch the remaining residue.
The tub program routine determines whether to repeat it. If the residue does not decrease, do not alternate increasingly strong cleaners: request an inspection and provide your observations.
Distinguish cleaning from prevention
A buildup of soap means you need to check the detergent dosage once the machine is clean. For a widespread wet film, see mold and biofilm. If the deposit seems mineral, use the limescale and water check before choosing an acid.
Cleaning the drum and tub addresses residue inside the machine. If you only see stains on clothing and no residue inside, follow the clothing stain check: do not assume every mark comes from dirt in the tub.
Save a description or photo of the residue for support if it continues. It is not necessary to disassemble the drum to document what is happening.