use strict;
use warnings;

sub clean {
    my $ref = shift;
    
    if ('HASH' eq ref $ref) {
        clean ($ref->{$_}), $ref->{$_} = undef for keys %$ref;
    } elsif ('ARRAY' eq ref $ref) {
        clean ($_), $_ = undef for @$ref;
    }
}


my $hashvar = {
    emp => {},
    hemp =>
        {splay => {}, hay => {go => 1, ho => {},}, tay => [], may => ['way'],},
        };

clean ($hashvar);
$hashvar = undef;