you can use the destroy method.

#!/usr/bin/perl
use Tk;
use strict;

my $mw =MainWindow->new(); # Main Window

my $frame = $mw->Frame() -> pack(); #New Frame
my $lbl = $frame->Label(-text => "some text")->pack();

my $but = $mw -> Button(-text=>"Destroy frame", -command =>\&destroy_f
+rame) -> pack();

MainLoop;

#This function will destroy the frame when the button is pushed
sub destroy_frame {
    $frame->destroy(); # destroy method called here
}
[download]

hope this helps,
davidj