diff --git a/CHANGES b/CHANGES
index 8b01248..b93e78b 100644
--- a/CHANGES
+++ b/CHANGES
@@ -49,6 +49,10 @@ Coding:
 	starting the data transfer loop. Useful, e.g., to accumulate multiple
 	packets in a receiving datagram socket before starting to process them.
 
+	"//" comments were used for disabling experimental code. These lines
+	have now been removed or disabled in other ways to make Socat compile
+	with C89/C90 standard again.
+
 Porting:
 	Small correction in configure.ac makes Socat C99 able.
 	Thanks to Florian Weimer from Red Hat for provinding a patch.
diff --git a/fdname.c b/fdname.c
index 872a9f4..1d32edc 100644
--- a/fdname.c
+++ b/fdname.c
@@ -367,7 +367,7 @@ int sockname(int fd, FILE *outfile, char style) {
 				 socknamebuff, sizeof(socknamebuff)));
       break;
      case 'S':
-	//sockettype(opttype, typename, TYPENAMEMAX);
+	/* sockettype(opttype, typename, TYPENAMEMAX); */
 	fprintf(outfile, "unix %s-%s %s %s",
 		sockaddr_unix_info(&sockname.un, socknamelen,
 				   socknamebuff, sizeof(socknamebuff)),
diff --git a/filan.c b/filan.c
index dbc54f0..b965eba 100644
--- a/filan.c
+++ b/filan.c
@@ -952,9 +952,11 @@ int tcpan2(int fd, FILE *outfile) {
    fprintf(outfile, "%s={%u}\t", "TCPI_OPTIONS", 	tcpinfo.tcpi_options);
    fprintf(outfile, "%s={%u}\t", "TCPI_SND_WSCALE", 	tcpinfo.tcpi_snd_wscale);
    fprintf(outfile, "%s={%u}\t", "TCPI_RCV_WSCALE", 	tcpinfo.tcpi_rcv_wscale);
-   //fprintf(outfile, "%s={%u}\t", "TCPI_DELIVERY_RATE_APP_LIMITED", tcpinfo.tcpi_delivery_rate_app_limited);
-   //fprintf(outfile, "%s={%u}\t", "TCPI_FASTOPEN_CLIENT_FAIL", tcpinfo.tcpi_fastopen_client_fail);
-   // fprintf(outfile, "%s={%u}\t", "TCPI_", tcpinfo.tcpi_);
+#if LATER
+   fprintf(outfile, "%s={%u}\t", "TCPI_DELIVERY_RATE_APP_LIMITED", tcpinfo.tcpi_delivery_rate_app_limited);
+   fprintf(outfile, "%s={%u}\t", "TCPI_FASTOPEN_CLIENT_FAIL", tcpinfo.tcpi_fastopen_client_fail);
+   fprintf(outfile, "%s={%u}\t", "TCPI_", tcpinfo.tcpi_);
+#endif
 
    return 0;
 }
diff --git a/socat.c b/socat.c
index 41f69a7..9e7b34a 100644
--- a/socat.c
+++ b/socat.c
@@ -1543,9 +1543,8 @@ void socat_signal(int signum) {
    case SIGINT:
       Notice1("exiting on signal %d", signum); break;
    }
-   //Exit(128+signum);
    Notice1("socat_signal(): finishing signal %d", signum);
-   diag_exit(128+signum);	/*!!! internal cleanup + _exit() */
+   diag_exit(128+signum);	/* internal cleanup + _exit() */
    diag_in_handler = 0;
    errno = _errno;
 }
diff --git a/xio-openssl.c b/xio-openssl.c
index 7d088cf..f393b9b 100644
--- a/xio-openssl.c
+++ b/xio-openssl.c
@@ -927,8 +927,6 @@ int
    unsigned long err;
    int result;
 
-   //*ipproto = IPPROTO_TCP;
-
    xfd->dtype = XIODATA_OPENSSL;
 
    retropt_bool(opts, OPT_OPENSSL_FIPS, &opt_fips);
diff --git a/xio-termios.c b/xio-termios.c
index 5835101..6edcea4 100644
--- a/xio-termios.c
+++ b/xio-termios.c
@@ -376,7 +376,6 @@ int xiotermios_speed(int fd, int n, speed_t speed) {
 	       &_xiotermios_data.termarg, speed, strerror(errno));
       }
    }
-// Tcgetattr(fd, &_xiotermios_data.termarg);
    return 0;
 }
 #endif /* HAVE_TERMIOS_ISPEED */
diff --git a/xioopts.c b/xioopts.c
index d0ecfae..e77ff96 100644
--- a/xioopts.c
+++ b/xioopts.c
@@ -2590,6 +2590,7 @@ int parseopts_table(const char **a, unsigned int groups, struct opt **opts,
 	 break;
 #endif /* defined(WITH_IP4) */
 
+#if LATER
       case TYPE_GENERIC:
 	 if (!assign) {
 	    (*opts)[i].value.u_int = 1;
@@ -2606,6 +2607,7 @@ int parseopts_table(const char **a, unsigned int groups, struct opt **opts,
 	    //(*opts)[i].value.u_bin.b_len
 	 }	 
 	 break;
+#endif /* LATER */
 
       default:
 	 Error2("parseopts_table(): internal error on option \"%s\": unimplemented type %d",