diff --git a/README.md b/README.md
index 38131e046..b01275190 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,7 @@ We added some options:
 * **delete_file_reference_after_seconds** (positive number) During cleanup, free the memory of the files that have not been touched for more than X seconds
 * **experiment_enable_file_reference_cleanup** (true/false) During cleanup, free the memory of the file references (Experimental!)
 * **experiment_debug_file_reference_cleanup** (true/false) During cleanup, print log messages about file references cleanup (Experimental!)
+* **experiment_enable_chat_access_hash_cleanup** (true/false) During cleanup, clean chats and channels access hash (Experimental!)
 
 ## Custom API functions
 ### TdApi.OptimizeMemory
diff --git a/td/telegram/ContactsManager.cpp b/td/telegram/ContactsManager.cpp
index 1cf9605c5..50385dda7 100644
--- a/td/telegram/ContactsManager.cpp
+++ b/td/telegram/ContactsManager.cpp
@@ -14685,6 +14685,7 @@ void ContactsManager::memory_cleanup() {
 
   auto user_ttl = !G()->shared_config().get_option_integer("delete_user_reference_after_seconds", 3600);
   auto chat_ttl = !G()->shared_config().get_option_integer("delete_chat_reference_after_seconds", 3600);
+  auto chat_access_hash_cleanup = !G()->shared_config().get_option_boolean("experiment_enable_chat_access_hash_cleanup", false);
 
   /* DESTROY INVALID USERS */
   {
@@ -14719,59 +14720,65 @@ void ContactsManager::memory_cleanup() {
   my_photo_file_id_.clear();
   my_photo_file_id_.rehash(0);
 
-  /* DESTROY INVALID CHATS */
-  {
-    auto it = chats_.begin();
-    while (it != chats_.end()) {
-      //auto &chat = it->second;
-      auto chat_id = it->first;
+  if (chat_access_hash_cleanup) {
+    /* DESTROY INVALID CHATS */
+    {
+      auto it = chats_.begin();
+      while (it != chats_.end()) {
+        //auto &chat = it->second;
+        auto chat_id = it->first;
 
-      auto is_invalid = time - chat_id.get_time() > chat_ttl;
+        auto is_invalid = time - chat_id.get_time() > chat_ttl;
 
-      if (is_invalid) {
-        chat_id.reset_time();
-        it = chats_.erase(it);
-      } else {
-        it++;
+        if (is_invalid) {
+          chat_id.reset_time();
+          it = chats_.erase(it);
+        } else {
+          it++;
+        }
       }
     }
-  }
 
-  chats_.rehash(0);
+    chats_.rehash(0);
+  }
   chats_full_.clear();
   chats_full_.rehash(0);
   unknown_chats_.clear();
   unknown_chats_.rehash(0);
-  chat_full_file_source_ids_.clear();
-  chat_full_file_source_ids_.rehash(0);
-  min_channels_.clear();
-  min_channels_.rehash(0);
+  if (chat_access_hash_cleanup) {
+    chat_full_file_source_ids_.clear();
+    chat_full_file_source_ids_.rehash(0);
+    min_channels_.clear();
+    min_channels_.rehash(0);
 
-  /* DESTROY INVALID CHANNELS */
-  {
-    auto it = channels_.begin();
-    while (it != channels_.end()) {
-      //auto &channel = it->second;
-      auto channel_id = it->first;
+    /* DESTROY INVALID CHANNELS */
+    {
+      auto it = channels_.begin();
+      while (it != channels_.end()) {
+        //auto &channel = it->second;
+        auto channel_id = it->first;
 
-      auto is_invalid = time - channel_id.get_time() > chat_ttl;
+        auto is_invalid = time - channel_id.get_time() > chat_ttl;
 
-      if (is_invalid) {
-        channel_id.reset_time();
-        it = channels_.erase(it);
-      } else {
-        it++;
+        if (is_invalid) {
+          channel_id.reset_time();
+          it = channels_.erase(it);
+        } else {
+          it++;
+        }
       }
     }
-  }
 
-  channels_.rehash(0);
-  channels_full_.clear();
-  channels_full_.rehash(0);
+    channels_.rehash(0);
+    channels_full_.clear();
+    channels_full_.rehash(0);
+  }
   unknown_channels_.clear();
   unknown_channels_.rehash(0);
-  channel_full_file_source_ids_.clear();
-  channel_full_file_source_ids_.rehash(0);
+  if (chat_access_hash_cleanup) {
+    channel_full_file_source_ids_.clear();
+    channel_full_file_source_ids_.rehash(0);
+  }
   //secret_chats_.clear();
   //secret_chats_.rehash(0);
   //unknown_secret_chats_.clear();
diff --git a/td/telegram/Td.cpp b/td/telegram/Td.cpp
index 9d3a2a151..8c80b1d2d 100644
--- a/td/telegram/Td.cpp
+++ b/td/telegram/Td.cpp
@@ -7345,6 +7345,9 @@ void Td::on_request(uint64 id, td_api::setOption &request) {
       if (set_boolean_option("experiment_debug_file_reference_cleanup")) {
         return;
       }
+      if (set_boolean_option("experiment_enable_chat_access_hash_cleanup")) {
+        return;
+      }
       break;
     case 'i':
       if (set_boolean_option("ignore_background_updates")) {