diff --git a/manual/administration/clean_database.md b/manual/administration/clean_database.md
index cc2670bc..cd463243 100644
--- a/manual/administration/clean_database.md
+++ b/manual/administration/clean_database.md
@@ -1,6 +1,6 @@
 # Clean Database
 
-### Session
+## Session
 
 Use the following command to clear expired session records in Seahub database:
 
@@ -12,6 +12,15 @@ cd seafile-server-latest
 !!! tip
     Enter into the docker image, then go to `/opt/seafile/seafile-server-latest`
 
+## Use clean_db_records command to clean seahub_db
+
+Use the following command to simultaneously clean up table records of Activity, sysadmin_extra_userloginlog, FileAudit, FileUpdate, FileHistory, PermAudit, FileTrash 90 days ago:
+
+```
+./seahub.sh python-env python3 seahub/manage.py clean_db_records
+```
+
+You can also clean these tables manually if you like as following.
 
 ### Activity
 
@@ -69,18 +78,11 @@ use seahub_db;
 DELETE FROM FileHistory WHERE to_days(now()) - to_days(timestamp) > 90;
 ```
 
-### Command clean_db_records
 
-Use the following command to simultaneously clean up table records of Activity, sysadmin_extra_userloginlog, FileAudit, FileUpdate, FileHistory, PermAudit, FileTrash 90 days ago:
 
-```
-./seahub.sh python-env python3 seahub/manage.py clean_db_records
-```
+## Clean outdated library data
 
-### Outdated Library Data
-
-Since version 6.2, we offer command to clear outdated library records in Seahub database,
-e.g. records that are not deleted after a library is deleted. This is because users can restore a deleted library, so we can't delete these records at library deleting time.
+Since version 6.2, we offer command to clear outdated library records in Seafile database, e.g. records that are not deleted after a library is deleted. This is because users can restore a deleted library, so we can't delete these records at library deleting time.
 
 ```
 ./seahub.sh python-env python3 seahub/manage.py clear_invalid_repo_data
@@ -97,8 +99,7 @@ This command has been improved in version 10.0, including:
 ```
 
 
-
-### Library Sync Tokens
+## Clean library sync tokens
 
 There are two tables in Seafile db that are related to library sync tokens.