def clean_text(text):
    """
    Given a block of text, clean it to remove unwanted characters other cruft.
    This will:
    1. Strip newlines - we don't care about them for word counts, 
    2. Cast to lowercase for consistency.
    3. Replace / with a space, retaining the words on either side of the /
    4. Replace "smart" quotes and apostrophes with dumb ones.
    """
    text = text.replace('\n', '').lower()
    text = text.replace('/', " ")
    text = text.replace('’', "'")
    return text