My dear old dad had a white Renault 11 in the 80s which was 6 months old when he had it. When he decided to px it for a newer car 5 years later my brother and I were tasked with giving it a clean. He hadn't cleaned it all through his ownership, inside or out. When we washed it the bucket of water used resembled emulsion paint. His policy of allowing cigarette ash to fall to the carpet to deter moths was evidently successful! Needless to say my brother and I keep our cars immaculate!