diff --git a/lowlevel/EvenProducer.java b/lowlevel/EvenProducer.java
index 6b665fde..5723685b 100644
--- a/lowlevel/EvenProducer.java
+++ b/lowlevel/EvenProducer.java
@@ -3,7 +3,6 @@
 // We make no guarantees that this code is fit for any purpose.
 // Visit http://OnJava8.com for more book information.
 // When threads collide
-// {ValidateByHand}
 
 public class EvenProducer extends IntGenerator {
   private int currentEvenValue = 0;
diff --git a/lowlevel/ExceptionThread.java b/lowlevel/ExceptionThread.java
index c9f7f82a..6664c454 100644
--- a/lowlevel/ExceptionThread.java
+++ b/lowlevel/ExceptionThread.java
@@ -2,7 +2,6 @@
 // (c)2017 MindView LLC: see Copyright.txt
 // We make no guarantees that this code is fit for any purpose.
 // Visit http://OnJava8.com for more book information.
-// {ValidateByHand}
 // {ThrowsException}
 import java.util.concurrent.*;
 
diff --git a/lowlevel/NaiveExceptionHandling.java b/lowlevel/NaiveExceptionHandling.java
index 0a1f9d1d..a765bcf9 100644
--- a/lowlevel/NaiveExceptionHandling.java
+++ b/lowlevel/NaiveExceptionHandling.java
@@ -2,7 +2,6 @@
 // (c)2017 MindView LLC: see Copyright.txt
 // We make no guarantees that this code is fit for any purpose.
 // Visit http://OnJava8.com for more book information.
-// {ValidateByHand}
 // {ThrowsException}
 import java.util.concurrent.*;