Very often the permanent loses tone for a poor rinsing when acid and water, remaining between the rollers (especially behind the neck), prevent the attachment of giving strength to permanent.
Väga sageli jäädavalt kaotab märguandetooni kehv loputamiseks, kui happe ja vee, jäädes vahemikku rullid (eriti taga kaela), takistavad kinnitamine annab tugevuse püsiv.