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1. Why is the exterior surface of the Jefferson Memorial deteriorating? The initial conclusion was that they had recently started using a more abrasive cleaner on the exterior surface. Rather than simply switch to a less abrasive cleaner, the custodial staff probed deeper.
2. Why are we using such an abrasive cleaner? A more abrasive cleaner was being used due to an increase of pigeon droppings on the Memorial.
3. Why has there been an increase in pigeon droppings on the memorial? Pigeons were attracted to the Memorial to feed on the large number of spiders attracted to the building.
4. Why are there so many spiders? The spiders were attracted to the Memorial to feed on the large number of gnats attracted to the building.
5. Why are there so many gnats? Gnats are most active at dusk. Some months ago, the lights surrounding the Memorial were adjusted to turn on at dusk attracting gnats.
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