You can use %load_number_hash = (); to clear the hash. Also delete will remove one key at a time. Here's an example.

use strict;
use warnings;

use Data::Dumper;

my @load_array = (0..9);

my %load_number_hash = ();
foreach(@load_array){
    $load_number_hash{$_} = $_;
}
print Dumper \%load_number_hash;

delete $load_number_hash{3};
print Dumper \%load_number_hash;

%load_number_hash = ();
print Dumper \%load_number_hash;
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Gives you the following output:

$VAR1 = {
          '0' => 0,
          '1' => 1,
          '2' => 2,
          '3' => 3,
          '4' => 4,
          '5' => 5,
          '6' => 6,
          '7' => 7,
          '8' => 8,
          '9' => 9
        };
$VAR1 = {
          '0' => 0,
          '1' => 1,
          '2' => 2,
          '4' => 4,
          '5' => 5,
          '6' => 6,
          '7' => 7,
          '8' => 8,
          '9' => 9
        };
$VAR1 = {};
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