Find non-ansi/ascii characters in a word file: Enter the following characters into the search box in Word, then enable “wildcards”. This will highlight each double-byte character one at a time.

[!^0013-^0255^t^m^x^z^l^n^11\@\* ]*

Due to a bug, it will also stop at the end of each table cell, however this is not because there are double-byte characters there.