Help getting rid of hard return in text file?

One of our coalitions decided to keep their mailing list in Outlook and use "enter" to separate address lines 1 & 2. In Excel .csv format, the list looks normal (1 row, 1 record) except the address field has a hard return in it for about 300 records which means that as a text file it is totally messed up. Now I need to mail to their list. Is there any relatively easy way to delete the hard return? I'm REALLY trying not to have to do this manually. Any ideas would be greatly appreciated.