diff --git a/C4/Auth.pm b/C4/Auth.pm
index 3769cde920..d59721d436 100755
--- a/C4/Auth.pm
+++ b/C4/Auth.pm
@@ -1338,9 +1338,7 @@ sub checkpw {
         $debug and print STDERR "## checkpw - checking CAS\n";
 	# In case of a CAS authentication, we use the ticket instead of the password
 	my $ticket = $query->param('ticket');
-	warn ("ticket : $ticket");
         my ($retval,$retcard,$retuserid) = checkpw_cas($dbh, $ticket, $query);    # EXTERNAL AUTH
-	warn "retval : $retval $retcard";
         ($retval) and return ($retval,$retcard,$retuserid);
 	return 0;
     }
diff --git a/C4/Auth_with_cas.pm b/C4/Auth_with_cas.pm
index d34d63e39f..5d4c3e0a59 100644
--- a/C4/Auth_with_cas.pm
+++ b/C4/Auth_with_cas.pm
@@ -31,6 +31,7 @@ use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS $debug);
 BEGIN {
 	require Exporter;
 	$VERSION = 3.03;	# set the version for version checking
+	$debug = $ENV{DEBUG};
 	@ISA    = qw(Exporter);
 	@EXPORT = qw(checkpw_cas login_cas logout_cas login_cas_url);
 }
@@ -50,7 +51,6 @@ sub logout_cas {
 sub login_cas {
     my ($query) = @_;
     my $cas = Authen::CAS::Client->new($casserver);
-    warn $cas->login_url(%ENV->{'SCRIPT_URI'});
     print $query->redirect($cas->login_url(%ENV->{'SCRIPT_URI'})); 
 }
 
@@ -63,14 +63,14 @@ sub login_cas_url {
 # Checks for password correctness
 # In our case : is there a ticket, is it valid and does it match one of our users ?
 sub checkpw_cas {
-    warn "checkpw_cas";
+    $debug and warn "checkpw_cas";
     my ($dbh, $ticket, $query) = @_;
     my $retnumber;
     my $cas = Authen::CAS::Client->new($casserver);
 
     # If we got a ticket
     if ($ticket) {
-	warn "Got ticket : $ticket";
+	$debug and warn "Got ticket : $ticket";
 	
 	# We try to validate it
 	my $val = $cas->service_validate(%ENV->{'SCRIPT_URI'}, $ticket);
@@ -79,7 +79,7 @@ sub checkpw_cas {
 	if( $val->is_success() ) {
 
 	    my $userid = $val->user();
-	    warn "User authenticated as: $userid";
+	    $debug and warn "User CAS authenticated as: $userid";
 
 	    # Does it match one of our users ?
     	    my $sth = $dbh->prepare("select cardnumber from borrowers where userid=?");
@@ -94,8 +94,12 @@ sub checkpw_cas {
 	    	$retnumber = $sth->fetchrow;
 		return (1, $retnumber, $userid);
 	    }
+	    
+	    # If we reach this point, then the user is a valid CAS user, but not a Koha user
+	    $debug and warn "User $userid is not a valid Koha user";
+
     	} else {
-    	    warn "Invalid session ticket : $ticket";
+    	    $debug and warn "Invalid session ticket : $ticket";
     	    return 0;
 	}
     }
@@ -115,8 +119,6 @@ C4::Auth - Authenticates Koha users
 
 =cut
 
-=head1 KOHA_CONF <usecasserver>http://mycasserver/loginurl</usecasserver>
-
 =head1 SEE ALSO
 
 CGI(3)