# unicode
tr/\x{2018}-\x{201B}/'/;
tr/\x{201C}-\x{201F}/"/;

# CP1252
tr/\x91\x92\x82/'/;
tr/\x93\x94\x84/"/;

# or, if you have UTF-8 data which isn't properly flagged as such,
# you can try to directly replace the multi-byte sequence, as
# they're encoded in UTF-8, e.g.
s/\xe2\x80\x98/'/g;  # one of the single quotes,
# ...                # and similarly for the 7 others...