diff --git a/core/src/main/java/google/registry/model/ImmutableObject.java b/core/src/main/java/google/registry/model/ImmutableObject.java
index fb615c714..3db9e4f8e 100644
--- a/core/src/main/java/google/registry/model/ImmutableObject.java
+++ b/core/src/main/java/google/registry/model/ImmutableObject.java
@@ -156,10 +156,6 @@ public abstract class ImmutableObject implements Cloneable {
    *   }
    * }
    * </pre>
-   *
-   * <p>This method makes use of {@link #toStringHelper}, which embeds {@link
-   * System#identityHashCode} in the output string. Subclasses that require deterministic string
-   * representations <em>across</em> JVM instances should override this method.
    */
   @Override
   public String toString() {
@@ -185,11 +181,9 @@ public abstract class ImmutableObject implements Cloneable {
 
   public String toStringHelper(SortedMap<String, Object> fields) {
     return String.format(
-        "%s (@%s): {\n%s",
-        getClass().getSimpleName(),
-        System.identityHashCode(this),
-        Joiner.on('\n').join(fields.entrySet()))
-            .replaceAll("\n", "\n    ") + "\n}";
+                "%s: {\n%s", getClass().getSimpleName(), Joiner.on('\n').join(fields.entrySet()))
+            .replaceAll("\n", "\n    ")
+        + "\n}";
   }
 
   /** Helper function to recursively hydrate an ImmutableObject. */
diff --git a/core/src/main/java/google/registry/model/common/Cursor.java b/core/src/main/java/google/registry/model/common/Cursor.java
index c3fb5b85d..2aca2ad80 100644
--- a/core/src/main/java/google/registry/model/common/Cursor.java
+++ b/core/src/main/java/google/registry/model/common/Cursor.java
@@ -19,9 +19,7 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import static google.registry.model.common.EntityGroupRoot.getCrossTldKey;
 import static google.registry.util.DateTimeUtils.START_OF_TIME;
 
-import com.google.common.base.Joiner;
 import com.google.common.base.Splitter;
-import com.google.common.collect.ImmutableSortedMap;
 import com.googlecode.objectify.Key;
 import com.googlecode.objectify.annotation.Entity;
 import com.googlecode.objectify.annotation.Id;
@@ -296,22 +294,5 @@ public class Cursor extends ImmutableObject implements DatastoreAndSqlEntity, Un
       this.type = type;
       this.scope = scope;
     }
-
-    /**
-     * A deterministic string representation of a {@link CursorId}. See {@link
-     * ImmutableObject#toString} for more information.
-     */
-    @Override
-    public String toString() {
-      return String.format(
-                  "%s: {\n%s",
-                  getClass().getSimpleName(),
-                  Joiner.on('\n')
-                      .join(
-                          ImmutableSortedMap.<String, Object>of("scope", scope, "type", type)
-                              .entrySet()))
-              .replaceAll("\n", "\n    ")
-          + "\n}";
-    }
   }
 }
diff --git a/core/src/main/java/google/registry/model/contact/ContactHistory.java b/core/src/main/java/google/registry/model/contact/ContactHistory.java
index 7a8f2061c..ab2f6de18 100644
--- a/core/src/main/java/google/registry/model/contact/ContactHistory.java
+++ b/core/src/main/java/google/registry/model/contact/ContactHistory.java
@@ -16,8 +16,6 @@ package google.registry.model.contact;
 
 import static google.registry.persistence.transaction.TransactionManagerFactory.jpaTm;
 
-import com.google.common.base.Joiner;
-import com.google.common.collect.ImmutableSortedMap;
 import com.googlecode.objectify.Key;
 import com.googlecode.objectify.annotation.EntitySubclass;
 import google.registry.model.EppResource;
@@ -202,24 +200,6 @@ public class ContactHistory extends HistoryEntry implements SqlEntity, UnsafeSer
     private void setId(long id) {
       this.id = id;
     }
-
-    /**
-     * A deterministic string representation of a {@link ContactHistoryId}. See {@link
-     * ImmutableObject#toString} for more information.
-     */
-    @Override
-    public String toString() {
-      return String.format(
-                  "%s: {\n%s",
-                  getClass().getSimpleName(),
-                  Joiner.on('\n')
-                      .join(
-                          ImmutableSortedMap.<String, Object>of(
-                                  "contactRepoId", getContactRepoId(), "id", getId())
-                              .entrySet()))
-              .replaceAll("\n", "\n    ")
-          + "\n}";
-    }
   }
 
   @Override
diff --git a/core/src/main/java/google/registry/model/domain/DomainHistory.java b/core/src/main/java/google/registry/model/domain/DomainHistory.java
index f26d028c2..e804fc42f 100644
--- a/core/src/main/java/google/registry/model/domain/DomainHistory.java
+++ b/core/src/main/java/google/registry/model/domain/DomainHistory.java
@@ -18,9 +18,7 @@ import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static google.registry.persistence.transaction.TransactionManagerFactory.jpaTm;
 import static google.registry.util.CollectionUtils.nullToEmptyImmutableCopy;
 
-import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.ImmutableSortedMap;
 import com.googlecode.objectify.Key;
 import com.googlecode.objectify.annotation.EntitySubclass;
 import google.registry.model.EppResource;
@@ -386,24 +384,6 @@ public class DomainHistory extends HistoryEntry implements SqlEntity {
     private void setId(long id) {
       this.id = id;
     }
-
-    /**
-     * A deterministic string representation of a {@link DomainHistoryId}. See {@link
-     * ImmutableObject#toString} for more information.
-     */
-    @Override
-    public String toString() {
-      return String.format(
-                  "%s: {\n%s",
-                  getClass().getSimpleName(),
-                  Joiner.on('\n')
-                      .join(
-                          ImmutableSortedMap.<String, Object>of(
-                                  "domainRepoId", getDomainRepoId(), "id", getId())
-                              .entrySet()))
-              .replaceAll("\n", "\n    ")
-          + "\n}";
-    }
   }
 
   @Override
diff --git a/core/src/main/java/google/registry/model/host/HostHistory.java b/core/src/main/java/google/registry/model/host/HostHistory.java
index 247f9e700..0831a65e6 100644
--- a/core/src/main/java/google/registry/model/host/HostHistory.java
+++ b/core/src/main/java/google/registry/model/host/HostHistory.java
@@ -16,8 +16,6 @@ package google.registry.model.host;
 
 import static google.registry.persistence.transaction.TransactionManagerFactory.jpaTm;
 
-import com.google.common.base.Joiner;
-import com.google.common.collect.ImmutableSortedMap;
 import com.googlecode.objectify.Key;
 import com.googlecode.objectify.annotation.EntitySubclass;
 import google.registry.model.EppResource;
@@ -205,24 +203,6 @@ public class HostHistory extends HistoryEntry implements SqlEntity, UnsafeSerial
     private void setId(long id) {
       this.id = id;
     }
-
-    /**
-     * A deterministic string representation of a {@link HostHistoryId}. See {@link
-     * ImmutableObject#toString} for more information.
-     */
-    @Override
-    public String toString() {
-      return String.format(
-                  "%s: {\n%s",
-                  getClass().getSimpleName(),
-                  Joiner.on('\n')
-                      .join(
-                          ImmutableSortedMap.<String, Object>of(
-                                  "hostRepoId", getHostRepoId(), "id", getId())
-                              .entrySet()))
-              .replaceAll("\n", "\n    ")
-          + "\n}";
-    }
   }
 
   @Override
diff --git a/core/src/main/java/google/registry/model/registrar/RegistrarContact.java b/core/src/main/java/google/registry/model/registrar/RegistrarContact.java
index 647cf4214..d4aefc041 100644
--- a/core/src/main/java/google/registry/model/registrar/RegistrarContact.java
+++ b/core/src/main/java/google/registry/model/registrar/RegistrarContact.java
@@ -32,9 +32,7 @@ import static java.util.stream.Collectors.joining;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Enums;
-import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.ImmutableSortedMap;
 import com.google.common.collect.ImmutableSortedSet;
 import com.google.common.collect.Streams;
 import com.googlecode.objectify.Key;
@@ -415,24 +413,6 @@ public class RegistrarContact extends ImmutableObject
       this.emailAddress = emailAddress;
       this.registrarId = registrarId;
     }
-
-    /**
-     * A deterministic string representation of a {@link RegistrarPocId}. See {@link
-     * ImmutableObject#toString} for more information.
-     */
-    @Override
-    public String toString() {
-      return String.format(
-                  "%s: {\n%s",
-                  getClass().getSimpleName(),
-                  Joiner.on('\n')
-                      .join(
-                          ImmutableSortedMap.<String, Object>of(
-                                  "emailAddress", emailAddress, "registrarId", registrarId)
-                              .entrySet()))
-              .replaceAll("\n", "\n    ")
-          + "\n}";
-    }
   }
 
   /** A builder for constructing a {@link RegistrarContact}, since it is immutable. */
diff --git a/core/src/test/java/google/registry/model/ImmutableObjectTest.java b/core/src/test/java/google/registry/model/ImmutableObjectTest.java
index a67bfc794..a84905391 100644
--- a/core/src/test/java/google/registry/model/ImmutableObjectTest.java
+++ b/core/src/test/java/google/registry/model/ImmutableObjectTest.java
@@ -68,11 +68,8 @@ public class ImmutableObjectTest {
   @Test
   void testToString_simpleClass() {
     SimpleObject object = new SimpleObject("foo", null);
-    assertThat(object.toString()).isEqualTo(""
-        + "SimpleObject (@" + System.identityHashCode(object) + "): {\n"
-        + "    a=foo\n"
-        + "    b=null\n"
-        + "}");
+    assertThat(object.toString())
+        .isEqualTo("" + "SimpleObject: {\n" + "    a=foo\n" + "    b=null\n" + "}");
   }
 
   @Test
@@ -332,8 +329,8 @@ public class ImmutableObjectTest {
 
     // The hash code test test is implicit in "equals", it is added here just for clarity.
     assertThat(instance1.hashCode()).isEqualTo(instance2.hashCode());
-    assertThat(instance1.toString()).matches(
-        "(?s)HasInsignificantFields (.*): \\{\\s*significant=significant\\s*\\}\\s*");
+    assertThat(instance1.toString())
+        .matches("(?s)HasInsignificantFields: \\{\\s*significant=significant\\s*\\}\\s*");
   }
 
   static class HasInsignificantFields extends ImmutableObject {