Zanussi ZDE 36150W Instruction Booklet page 12

Important:
Do not use the appliance without filters.
Cleaning the drum
When your laundry does not reach the desired
degree of dryness, in other words, when it turns
out either too dry or too damp, we advise you to
clean the inside of the drum with a cloth soaked
with vinegar.
This will eliminate the slight patina that has
formed in the drum (due to residues of detergent
and softeners used in the washing, and to the
lime contained in the water), which prevents the
probes from detecting the correct degree of
dryness.
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