There are 2 options to remove Non-Ascii characters:
 

1. Using File Cleaner ( TxDialer > Tools > File Cleaner ).

The file containing non-ascii characters can be uploaded and the cleaned file would be downloaded.
Use File Check ( TxDialer > Tools > File Check ) to look for  special and non-ascii characters

2. Using Notepad ++

How to remove all non ascii characters with regex?

Install Notepad++ Editor from https://notepad-plus-plus.org/


Using Notepad++

Open the .csv file.

Goto Menu > Search > Find...

This expression will search for non-ascii values:  [^\x00-\x7F]+
Find and remove all the non ascii characters .

Tick off 'Search Mode = Regular expression', and check 'Search Mode = Extended'.

Replace following characters
\r with  <blank>
 – with -
" with <blank>

Save the file.
Note: Use 'Save As/Save Copy' to retain the original file for comparison