diff --git a/xorriso/xorriso.1 b/xorriso/xorriso.1
index 8f1146cb..ec4c9353 100644
--- a/xorriso/xorriso.1
+++ b/xorriso/xorriso.1
@@ -162,9 +162,10 @@ capabilities.
 suitable for xorriso.
 .br
 Blank is the state of newly purchased optical media.
-With used CD-RW and DVD-RW it can be achieved by action -blank fast.
+With used CD-RW and DVD-RW it can be achieved by action -blank "fast".
 Overwriteable media are considered blank unless they contain an ISO image
-suitable for xorriso.
+suitable for xorriso. Action -blank "fast" can be used to invalidate the image
+on overwriteable media.
 .br
 \fBAppendable\fR media accept further sessions. Either they are MMC
 multi-session media in appendable state, or they are overwriteable media