$text   =~ s|/\*          # First slash and star /*
             (?:          # Non-backreferencing parentheses
                (?!\*/)   # not a star slash */
                .         # ok to inch along
             )*           # Zero or more
           \*/||sx;       # Followed by a star slash */

##</code><code>##

my $text = 'foo /* bar **/ baz /* ack! ph! */';
$text =~ s|
              \/\*       # '/*', escaped
                [^\*]*   # 0 or more non-'*' characters
              \*\/       # '*/', escaped
          ||x;
print $text;