Deleting multiple layouts

1)
I have to clean up 1000 FWG Filmes with euch 50-100 Layouts. Only One Layout will be kept in a dwg file.
What is the fastes Way to do this?
I know with Ctrl i can select them, but this will Take forever...
2)
In the modelspace i have to erase everything that is Not on the One Layout. So far i have market with a line in the Layout which items i Need to keep.
Any Other solutions?

Thanks in Advanced!