I am working on AIX. We ftp files to a database. The flat files are having thousands of records and each record is having some 50 to 60 characters(there are fields having certain character length). In addition to some valid ascii characters some invalid characters like Å, å, Ä, ä or pipes creep in which datawarehouse rejects to load in.
Example: AcuM-^?a 051706 ;
above is a field in the record which is having special characters like -,^ and ? , which should not have been there.

The record separator is a new line and there is no field seperator.

How can I remove these invalid or special characters to creep in the records?
Please help me to find the logic in the shell sripting..