Freeing memory used by QTableItem

Hello,

how can I free memory used by an object of class Qt::TableItem myself?
I've read that takeItem only removes an item from an existing table 
without destroying the Qt::TableItem object.
So since I can't simply say "delete <object>" in Perl I tried the following:

my @t = ();
for (my $i=0 ;$i<1000 ;$i++ )
{
      $t[$i] = Qt::TableItem(table,&Qt::TableItem::Never,"$i");
}

sleep(10);

for (my $i=0 ;$i<1000 ;$i++ )
{
    $t[$i] = "";
}

But "top" shows me that memory usage after the last loop increases 
instead of decreases.

Thanks for your help,
Oliver