Using a linux shell command called iconv you can convert content of a file from one encoding to another.
If you know exactly what format its in:
iconv --from-code=LATIN1 --to-code=UTF8 -c --output=~/test/xml/input_clean.xml ~/test/xml/input.xml
The "-c" option tells the program to omit unmappable characters. Otherwise it will stop at the first unmappable character it encounters.