cat "multibyte or wide character" error

[blaster666]

Hi all. trying to compare and uniq 2 .txt files. Getting this error:
sort: string comparison failed: Invalid or incomplete multibyte or wide character
sort: Set LC_ALL='C' to work around the problem.
sort: The strings compared were ‘sorient\342t\r’ and ‘sorient\350rent\r’.

I would be so grateful, if you could advise me how to avoid it. 
Manuall string delete is not working for me, as .txt is really large

I have found that it was because of strings, containing unprintable characters. How could i remove all of them from the txt file? 
I mean, to remove all the strings containing unprintable characters or smth

[Snoopy]

first, dont open up new threads for questions which are  popping up after recieving an answer in another thread, use the old one

second, one possible answer is already given by sort

Code:

Set LC_ALL='C' to work around the problem.

never the less, there is another great linux tool called iconv

Code:

iconv -c input.txt > output.txt or iconv -c -t=UTF-8 input.txt > output.txt

this will strip unprintable chars from input, but never the less, it seems your input files are malformed or have been through some seriuos misconversion between different character encodings which will mostly result in these problems you mentioned