How to clean up hidden characters

These days, I made many comma delimited text files exports from my ACCESS 97 tables. When one of my friends tried to import them in EXCEL, some records were damaged. When I checked the tables, I found that those records are containing hidden carriage return/line feed characters (CTRL+ENTER). Is there anybody who can help me with a solution for this problem? So far, I found out that I could use some functions to replace those characters with ? ? or ?_? (i.e., InStr()), but I don?t know the character codes for these key strokes (Chr$() ?).
Thank you very much for any idea regarding this issue.

Lucian
lucsel@home.com