REMOVE

1. freight cars
2. rubbish
3. sidewalks
4. coats (garments)
5. automobiles
6. buildings (structures)

WHAT

1. Visual Works (hierarchy n … (2)
2. artists (visual artists) (2)
3. black-and-white film (2)
4. eyeglasses (2)
5. fences (2)

More 

WHERE

1. New York, New York (2)

WHO

1. Diane Still Knox; Diane K … (1)
2. Knox, Diane Still (1)

WHEN

1. 1957 (1)
2. 1958 (1)