You haven't been doing anything like this, have you? 
$h{1, 2} = "hello";

[download]
This creates a key consisting of three characters: "1", $SUBSEP and "2". $SUBSEP has a default octal value of 034 (aka Ctrl-\).

my %h;
$h{1, 2} = "hello";
$Data::Dumper::Useqq = 1;
print Dumper \%h;

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From perlvar:

$SUBSCRIPT_SEPARATOR
$SUBSEP
$;      The subscript separator for multidimensional array emulation. 
+If
        you refer to a hash element as

            $foo{$a,$b,$c}

        it really means

            $foo{join($;, $a, $b, $c)}

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In reply to Re: Subtracting Stringified Negative Numbers by FunkyMonk
in thread Subtracting Stringified Negative Numbers by monkfan

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