Hi Fandorin, Sorry that I've had to revise it so drastically, but it is now more understandable at least to me. Cause and nature of extensive stains appearing on the upholstery fabric of a car's headliner: When a vehicle is stored outside and/or in a parking area without temperature regulation, the waterproof headiner fabric is liable to accumulate moisture, leading to water condensation between the car roof and its covering. When the accumulation of water exceeds the capacity of the headliner to absorb and contain it, the water drips and generates blots at the edges of the covering.
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