Visible mould-like deposits may be removed while pale yellow or brown marks remain. Deposits, residual colour and textile damage are different issues. Further work depends on what remains and what the fabric can tolerate.
Identify the stage
Ongoing dampness, extensive contamination or visible mould-like growth calls for isolation and professional assessment before appearance work. This discussion concerns residual marks on a dry surface after deposit treatment. No visible mould does not establish microbiological testing or justify a promise of no recurrence.
Map depth, distribution and marks crossing seams, inspecting the inner and accessible layered areas. On canvas-and-leather items such as a Herbag, record both materials separately.
Colour and fibre condition together
Magnify the weave for fuzzing, thinning, broken yarns or stiffness and compare a sound area without picking with a needle or pulling hard. A pale-brown mark with intact weave differs from a lighter mark already abraded. The latter is not a reason to keep cleaning because it is almost gone.
What new evidence supports another pass?
Review the previous product, scope, dry improvement and new boundaries. Repeated wet lightening followed by the same dry mark is not progress. Reassess where the colour sits and whether the material permits further treatment.
Confirm compatibility with canvas, dyes, leather joins and hardware before stain or colour removal. Success on one fabric cannot simply be applied to a complete mixed-material bag, and unknown household mixtures add uncertainty. Stop for colour migration or fibre changes.
Describe an acceptable result
Record visibility at normal distance, close up and inside. Discuss retaining slight residual colour, further-treatment risk or a component-related option where appropriate. Overexposed photographs that hide pale marks are not evidence of removal.
Before handover, confirm suitable dryness and stable joins and inner areas, and give moisture-control advice suited to the actual storage environment. Investigate any later changes rather than automatically blaming customer use.
For each pass, record only the dry colour result—unchanged, slight or clear improvement—alongside a separate fibre-condition field and any new tide marks. Slight colour improvement with fuzzing may not justify continuing. Without stable dry photographs, improve observation first.
REBIRTH's Hermès Herbag canvas mould-mark case and cleaning-material lessons can be reviewed under three headings: deposits, remaining marks and fibre condition. Knowing when to stop is a core part of reducing rework and damage.