diff --git a/src/blenderbim/blenderbim/bim/module/cost/operator.py b/src/blenderbim/blenderbim/bim/module/cost/operator.py
index 320e3840f7..02c7b2e9a8 100644
--- a/src/blenderbim/blenderbim/bim/module/cost/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/cost/operator.py
@@ -163,7 +163,7 @@ class RemoveCostItem(bpy.types.Operator, tool.Ifc.Operator):
     cost_item: bpy.props.IntProperty()
 
     def _execute(self, context):
-        core.remove_cost_item(tool.Ifc, tool.Cost, cost_item=tool.Ifc.get().by_id(self.cost_item))
+        core.remove_cost_item(tool.Ifc, tool.Cost, cost_item_id=self.cost_item)
 
 
 class EnableEditingCostItem(bpy.types.Operator, tool.Ifc.Operator):
diff --git a/src/blenderbim/blenderbim/core/cost.py b/src/blenderbim/blenderbim/core/cost.py
index 4cc4db3d5b..e0afbe999e 100644
--- a/src/blenderbim/blenderbim/core/cost.py
+++ b/src/blenderbim/blenderbim/core/cost.py
@@ -59,9 +59,10 @@ def contract_cost_items(cost):
     cost.load_cost_schedule_tree()
 
 
-def remove_cost_item(ifc, cost, cost_item):
+def remove_cost_item(ifc, cost, cost_item_id):
+    cost_item = ifc.get().by_id(cost_item_id)
     ifc.run("cost.remove_cost_item", cost_item=cost_item)
-    cost.clean_up_cost_item_tree(cost_item)
+    cost.clean_up_cost_item_tree(cost_item_id)
     cost.load_cost_schedule_tree()
 
 
diff --git a/src/blenderbim/blenderbim/tool/cost.py b/src/blenderbim/blenderbim/tool/cost.py
index f007e6ff01..aef65f093c 100644
--- a/src/blenderbim/blenderbim/tool/cost.py
+++ b/src/blenderbim/blenderbim/tool/cost.py
@@ -96,11 +96,11 @@ class Cost(blenderbim.core.tool.Cost):
         props.contracted_cost_items = json.dumps(cls.contracted_cost_items)
 
     @classmethod
-    def contract_cost_item(cls, cost_item):
+    def contract_cost_item(cls, cost_item_id):
         props = bpy.context.scene.BIMCostProperties
         if not hasattr(cls, "contracted_cost_items"):
             cls.contracted_cost_items = json.loads(props.contracted_cost_items)
-        cls.contracted_cost_items.append(cost_item.id())
+        cls.contracted_cost_items.append(cost_item_id)
         props.contracted_cost_items = json.dumps(cls.contracted_cost_items)
 
     @classmethod
@@ -114,11 +114,11 @@ class Cost(blenderbim.core.tool.Cost):
         props.contracted_cost_items = json.dumps(cls.contracted_cost_items)
 
     @classmethod
-    def clean_up_cost_item_tree(cls, cost_item):
+    def clean_up_cost_item_tree(cls, cost_item_id):
         props = bpy.context.scene.BIMCostProperties
         if not hasattr(cls, "contracted_cost_items"):
             cls.contracted_cost_items = json.loads(props.contracted_cost_items)
-        if props.active_cost_item_id == cost_item.id():
+        if props.active_cost_item_id == cost_item_id:
             props.active_cost_item_id = 0
         if props.active_cost_item_index in cls.contracted_cost_items:
             cls.contracted_cost_items.remove(props.active_cost_item_index)