use warnings;
use strict;
use XML::Twig;

my $twig = new XML::Twig(
    twig_handlers => {
        item => \&item,
    },
);
$twig->parsefile('in.xml');
$twig->set_pretty_print('indented');
$twig->print_to_file('out.xml');

sub item {
    my ( $twig, $item ) = @_;
    for my $c ($item->children()) {
        $c->cut($item) unless
            $c->tag() eq 'id' or
            $c->tag() eq 'name'
        ;
    }
}