...
system('scp', '/users/myuser/merc/rem_snew.pl', "$remoteuser\@$remoteserver:/users/$remoteuser/tmp/rem_snew2.pl");

my $result = `ssh $remoteuser\@$remoteserver perl /users/$remoteuser/tmp/rem_snew2.pl`;

print "$result\n";
system('ssh', "$remoteuser\@$remoteserver", 'rm', ...);