I would try the following:

- Create a new field in your table to receive the changed data - a
nice safety idea
- Open New Query in design view
- drag in the table
- drag the field containing "�" to the bottom pane, I'll call it
[CodeField] for now
- drag the [NewField] to the bottom pane
- click the "Query Type" button and select Update Query
- In the [Codefield] Criteria line, put
Like "�"
- In the [Newfield] UpDateTo line, put
"" or " "

Click the big fat exclamation mark which will run the update.

hope that helps ...