my $debug = 1;

my @oldest_10_files = (
    map { $_->[1] }
    sort { $b->[0] <=> $a->[0] }
    map { [ -M $_, $_ ] }
    glob( "/path/to/directory/*" )
)[0..9];

unlink @oldest_10_files unless $debug;

print "The following files have been removed\n\n", join "\n", @oldest_10_files;