diff --git a/dp3/database/database.py b/dp3/database/database.py
index a9220d0d..efb4b292 100644
--- a/dp3/database/database.py
+++ b/dp3/database/database.py
@@ -671,14 +671,30 @@ def get_raw_summary(self, etype: str, before: datetime) -> pymongo.cursor:
         except Exception as e:
             raise DatabaseError(f"Raw collection {raw_col_name} fetch failed: {e}") from e
 
-    def get_raw(self, etype: str, after: datetime, before: datetime) -> pymongo.cursor:
+    def get_raw(
+        self, etype: str, after: datetime, before: datetime, plain: bool = True
+    ) -> pymongo.cursor:
+        """Get raw datapoints where `t1` is in <`after`, `before`).
+
+        If `plain` is `True`, then all plain datapoints will be returned (default).
+        """
         raw_col_name = self._raw_col_name(etype)
-        return self._db[raw_col_name].find({"t1": {"$gte": after, "$lt": before}})
+        query_filter = {"$or": [{"t1": {"$gte": after, "$lt": before}}]}
+        if plain:
+            query_filter["$or"].append({"t1": {"$exists": False}})
+        return self._db[raw_col_name].find(query_filter)
 
-    def delete_old_raw_dps(self, etype: str, before: datetime):
+    def delete_old_raw_dps(self, etype: str, before: datetime, plain: bool = True):
+        """Delete raw datapoints older than `before`.
+
+        Deletes all plain datapoints if `plain` is `True` (default).
+        """
         raw_col_name = self._raw_col_name(etype)
+        query_filter = {"$or": [{"t1": {"$lt": before}}]}
+        if plain:
+            query_filter["$or"].append({"t1": {"$exists": False}})
         try:
-            return self._db[raw_col_name].delete_many({"t1": {"$lt": before}})
+            return self._db[raw_col_name].delete_many(query_filter)
         except Exception as e:
             raise DatabaseError(f"Delete of old datapoints failed: {e}") from e
 
diff --git a/dp3/history_management/history_manager.py b/dp3/history_management/history_manager.py
index 70d80a2d..c08efe54 100644
--- a/dp3/history_management/history_manager.py
+++ b/dp3/history_management/history_manager.py
@@ -189,7 +189,7 @@ def archive_old_dps(self):
                 first = True
 
                 for etype in self.model_spec.entities:
-                    result_cursor = self.db.get_raw(etype, after=min_date, before=t_old)
+                    result_cursor = self.db.get_raw(etype, after=min_date, before=t_old, plain=True)
                     for dp in result_cursor:
                         if first:
                             logfile.write(
@@ -209,7 +209,7 @@ def archive_old_dps(self):
 
         deleted_count = 0
         for etype in self.model_spec.entities:
-            deleted_res = self.db.delete_old_raw_dps(etype, before=t_old)
+            deleted_res = self.db.delete_old_raw_dps(etype, before=t_old, plain=True)
             deleted_count += deleted_res.deleted_count
         self.log.info("Deleted %s datapoints", deleted_count)