def get_clean_block(block):
    """Clean up unicode characters and common OCR errors in blocks"""
    replacements = {'ﬁ': 'fi',
                    'ﬂ': 'fi',
                    '—': '-',
                    "’": "'",
                    "‘": "'",
                    '”': '"',
                    '“': '"',
                    'km3': 'km2',
                    'kmz': 'km2',
                    '\\N': 'W',
                    'VV': 'W',
                    'lVI': 'M',
                    '\x0c': ''}
    for replacement in replacements:
        if replacement in block:
            block = block.replace(replacement, replacements[replacement])
    return(block)