How to clean a structure?

gistfile1.txt

my $unclean_data = {
		field_1 => 'value',
		field_2 => 'value',
		do_NOT_leak => 'private info',
		wibble => [
			{
				other_private_info => 'private info',
				field_3 => 'value',
				field_4 => 'value',
			},
			{
				other_private_info => 'private info',
				field_3 => 'value',
				field_4 => 'value',
			},
		],
}

my $ok_structure => {
		field_1 => 1,
		field_2 => 1,
		wibble => [
			{
				field_3 => 1,
				field_4 => 1,
			}
		],
}


my $clean_data = CleanData->run($unclean_data, $bos_data);

So $clean_data is then:
{
		field_1 => 'value',
		field_2 => 'value',
		wibble => [
			{
				field_3 => 'value',
				field_4 => 'value',
			},
			{
				field_3 => 'value',
				field_4 => 'value',
			},
		],
}