An unknown treatment history can alter the response to new cleaners, colour coats, finishes or adhesives. Record this uncertainty before work begins.
What to examine
- Covered stitching, unusual sheen and coating thickness.
- Previous cleaning and repair information from the customer.
- Layers visible at naturally worn areas.
- Dissolving, tackiness and colour transfer during a controlled test.
Working sequence
- Flag the unknown history on the job record.
- Keep tests small and inconspicuous.
- Allow progressively longer observation for stability.
- Stop further work if compatibility cannot be established.
Removing the entire old layer should not be the default. Forced stripping may damage the original surface underneath.