diff --git a/csst_common/data_manager.py b/csst_common/data_manager.py
index 58625971a30e58f6dfaeeafeecf01cfd122ee265..9a7ab5b2d3720b7442cc3d737000fcd4ecb9f747 100644
--- a/csst_common/data_manager.py
+++ b/csst_common/data_manager.py
@@ -608,7 +608,8 @@ class CsstMsDataManager:
             dir_l0="/L1Pipeline/L0",
             dir_l1="/L1Pipeline/L1",
             use_dfs=True,
-            dfs_node="pml"
+            dfs_node="pml",
+            clear_l1=False,
     ):
         """ Initialize CsstMsDataManager from DFS. """
         # (clear and) make directories
@@ -623,6 +624,8 @@ class CsstMsDataManager:
         # os.chdir(dir_l1)
         if not os.path.exists(dir_l1):
             os.mkdir(dir_l1)
+        elif clear_l1:
+            os.system(f"rm -rf {dir_l1}/*")
         os.chdir(dir_l1)
 
         print(f"Query obs_id={obs_id} ...", end="")