my $stamp;    # set to appropriate epoch time stamp
my @files = $ftp->ls();
chomp( @files );

for my $file ( @files ) {
    print "Testing file : $file\n";
    if ( $file !~ /\.stm$/ ) {
        print "Skipping : $file is not an .stm file\n";
        next;
    }
    my $mtime = $ftp->mdtm($file);
    die "cannot get mdtm for $file\n" if ! $mtime;
    print "$file last modified : ", scalar localtime($mtime), "\n";
    if ( $mtime < $stamp ) {
        print "Removing file : $file\n";
        $ftp->delete($file);
        print $ftp->message, "\n";
    }
}