diff --git a/rtc_base/thread.h b/rtc_base/thread.h
index 34848308c4..52df554f24 100644
--- a/rtc_base/thread.h
+++ b/rtc_base/thread.h
@@ -29,7 +29,6 @@
 #endif
 #include "absl/base/attributes.h"
 #include "absl/functional/any_invocable.h"
-#include "absl/memory/memory.h"
 #include "api/function_view.h"
 #include "api/task_queue/task_queue_base.h"
 #include "api/units/time_delta.h"
@@ -298,14 +297,6 @@ class RTC_LOCKABLE RTC_EXPORT Thread : public webrtc::TaskQueueBase {
     return messages_.size() + delayed_messages_.size();
   }
 
-  // Internally posts a message which causes the doomed object to be deleted
-  // TODO(bugs.webrtc.org/8324): Delete when unused by dependencies.
-  template <class T>
-  void Dispose(T* doomed) {
-    RTC_DCHECK(doomed);
-    PostTask([dommed = absl::WrapUnique(doomed)] {});
-  }
-
   bool IsCurrent() const;
 
   // Sleeps the calling thread for the specified number of milliseconds, during
@@ -509,8 +500,6 @@ class RTC_LOCKABLE RTC_EXPORT Thread : public webrtc::TaskQueueBase {
 
   friend class ScopedDisallowBlockingCalls;
 
-  RecursiveCriticalSection* CritForTest() { return &crit_; }
-
  private:
   static const int kSlowDispatchLoggingThreshold = 50;  // 50 ms
 
diff --git a/rtc_base/thread_message.h b/rtc_base/thread_message.h
index cf38338f43..dbde40b0f0 100644
--- a/rtc_base/thread_message.h
+++ b/rtc_base/thread_message.h
@@ -89,8 +89,6 @@ class DisposeData : public MessageData {
 };
 
 const uint32_t MQID_ANY = static_cast<uint32_t>(-1);
-// TODO(bugs.webrtc.org/8324): Delete when unused by dependencies.
-const uint32_t MQID_DISPOSE = static_cast<uint32_t>(-2);
 
 // No destructor
 
diff --git a/rtc_base/thread_unittest.cc b/rtc_base/thread_unittest.cc
index c88233998b..a800671a0b 100644
--- a/rtc_base/thread_unittest.cc
+++ b/rtc_base/thread_unittest.cc
@@ -555,42 +555,6 @@ TEST(ThreadTest, ThreeThreadsInvoke) {
   EXPECT_TRUE_WAIT(thread_a_called.Get(), 2000);
 }
 
-class ThreadQueueTest : public ::testing::Test, public Thread {
- public:
-  ThreadQueueTest() : Thread(CreateDefaultSocketServer(), true) {
-    RTC_DCHECK(Thread::Current() == nullptr);
-    ThreadManager::Instance()->SetCurrentThread(this);
-  }
-  ~ThreadQueueTest() { ThreadManager::Instance()->SetCurrentThread(nullptr); }
-  bool IsLocked_Worker() {
-    if (!CritForTest()->TryEnter()) {
-      return true;
-    }
-    CritForTest()->Leave();
-    return false;
-  }
-  bool IsLocked() {
-    // We have to do this on a worker thread, or else the TryEnter will
-    // succeed, since our critical sections are reentrant.
-    std::unique_ptr<Thread> worker(Thread::CreateWithSocketServer());
-    worker->Start();
-    return worker->Invoke<bool>(RTC_FROM_HERE,
-                                [this] { return IsLocked_Worker(); });
-  }
-};
-
-struct DeletedLockChecker {
-  DeletedLockChecker(ThreadQueueTest* test, bool* was_locked, bool* deleted)
-      : test(test), was_locked(was_locked), deleted(deleted) {}
-  ~DeletedLockChecker() {
-    *deleted = true;
-    *was_locked = test->IsLocked();
-  }
-  ThreadQueueTest* test;
-  bool* was_locked;
-  bool* deleted;
-};
-
 static void DelayedPostsWithIdenticalTimesAreProcessedInFifoOrder(
     FakeClock& clock,
     Thread& q) {
@@ -614,7 +578,7 @@ static void DelayedPostsWithIdenticalTimesAreProcessedInFifoOrder(
   EXPECT_THAT(run_order, ElementsAre(0, 1, 2, 3, 4));
 }
 
-TEST_F(ThreadQueueTest, DelayedPostsWithIdenticalTimesAreProcessedInFifoOrder) {
+TEST(ThreadTest, DelayedPostsWithIdenticalTimesAreProcessedInFifoOrder) {
   ScopedBaseFakeClock clock;
   Thread q(CreateDefaultSocketServer(), true);
   q.Start();
@@ -626,39 +590,6 @@ TEST_F(ThreadQueueTest, DelayedPostsWithIdenticalTimesAreProcessedInFifoOrder) {
   DelayedPostsWithIdenticalTimesAreProcessedInFifoOrder(clock, q_nullss);
 }
 
-TEST_F(ThreadQueueTest, DisposeNotLocked) {
-  bool was_locked = true;
-  bool deleted = false;
-  DeletedLockChecker* d = new DeletedLockChecker(this, &was_locked, &deleted);
-  Dispose(d);
-  Message msg;
-  ProcessMessages(0);
-  EXPECT_TRUE(deleted);
-  EXPECT_FALSE(was_locked);
-}
-
-class DeletedMessageHandler : public MessageHandlerAutoCleanup {
- public:
-  explicit DeletedMessageHandler(bool* deleted) : deleted_(deleted) {}
-  ~DeletedMessageHandler() override { *deleted_ = true; }
-  void OnMessage(Message* msg) override {}
-
- private:
-  bool* deleted_;
-};
-
-TEST_F(ThreadQueueTest, DisposeHandlerWithPostedMessagePending) {
-  bool deleted = false;
-  DeletedMessageHandler* handler = new DeletedMessageHandler(&deleted);
-  // First, post a dispose.
-  Dispose(handler);
-  // Now, post a message, which should *not* be returned by Get().
-  Post(RTC_FROM_HERE, handler, 1);
-  Message msg;
-  ProcessMessages(0);
-  EXPECT_TRUE(deleted);
-}
-
 // Ensure that ProcessAllMessageQueues does its essential function; process
 // all messages (both delayed and non delayed) up until the current time, on
 // all registered message queues.