foreach (sort {-M $a <=> -M $b} <*>)
{
    # ...
}

##</code><code>##

$oldest = 5;  # Days
$newest = 1;

foreach (<*>)
{
      next unless (-M $_ < $oldest && -M $_ > $newest);

      # Do stuff
}

##</code><code>##

$oldest = 5;  # Days
$newest = 1;

foreach (grep {-M $_ < $oldest && -M $_ > $newest} <*>)
{
      # Do stuff
}