You're still posting snippets of what you think is going on, instead of snippets of real code. For example, your latest snippet simply doesn't do what you are suggesting it does:

use Data::Dumper; 
$Data::Dumper::Useqq=1; 
my $some_string = "0,-933"; 

print Dumper $some_string;
$VAR1 = "0,-933";
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So my questions are:

• How can this \34 comes, in the first place? Can we avoid that?
• My development is always under Linux/Unix platform. And those variable values are read from a file.
• How to remove this \34 character from $VAR?

The only conclusion we can draw from what you've posted so far is that the file you are reading these values from contains these \x1c (octal \34) characters.

Try dumping the file using the od command:

od -b \path\to\the\file
# or
od -tx1 \path\to\the\file
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