diff --git a/nomenclature/codelist.py b/nomenclature/codelist.py
index d9cb7039..a883a199 100644
--- a/nomenclature/codelist.py
+++ b/nomenclature/codelist.py
@@ -595,11 +595,15 @@ def check_weight_in_vars(cls, v):
             )
         return v
 
-    def vars_default_args(self, variables: list[str]) -> list[VariableCode]:
+    def vars_default_args(self, variables: list[str]) -> list[str]:
         """return subset of variables which does not feature any special pyam
         aggregation arguments and where skip_region_aggregation is False"""
+        # this is where the problem lies
+        # say we have a variable code that is Primary Energy* and a variable in variables called Primary Energy|1
+        # Our lookup will never work since Primary Energy* is not the same as Primary Energy|1. But we need to uniquely identify which variable pattern we're matching to get aggregation information agg_kwargs and skip_region_aggregation
+        # we need to perform a wildcard match of var on self and then look up the result (WHICH HAS TO BE UNQIUE -> https://github.com/IAMconsortium/nomenclature/issues/432) and get VariableCode.agg_kwargs and VariableCode.skip_region_aggregation
         return [
-            self[var]
+            var
             for var in variables
             if not self[var].agg_kwargs and not self[var].skip_region_aggregation
         ]
@@ -621,8 +625,7 @@ def validate_units(
         if invalid_units := [
             (variable, unit, self.mapping[variable].unit)
             for variable, unit in unit_mapping.items()
-            if variable in self.variables
-            and unit not in self.mapping[variable].units
+            if variable in self.variables and unit not in self.mapping[variable].units
         ]:
             lst = [
                 f"'{v}' - expected: {'one of ' if isinstance(e, list) else ''}"
diff --git a/nomenclature/processor/region.py b/nomenclature/processor/region.py
index 06b56ec9..976223d6 100644
--- a/nomenclature/processor/region.py
+++ b/nomenclature/processor/region.py
@@ -646,7 +646,7 @@ def _apply_region_processing(
 
                     # first, perform 'simple' aggregation (no arguments)
                     simple_vars = [
-                        var.name
+                        var
                         for var in self.variable_codelist.vars_default_args(
                             model_df.variable
                         )
diff --git a/tests/data/region_processing/dsd/variable/variables.yaml b/tests/data/region_processing/dsd/variable/variables.yaml
index ede21a94..7df1bc65 100644
--- a/tests/data/region_processing/dsd/variable/variables.yaml
+++ b/tests/data/region_processing/dsd/variable/variables.yaml
@@ -4,6 +4,9 @@
 - Primary Energy|Coal:
     definition: Primary energy consumption of Coal
     unit: EJ/yr
+- Primary Energy|*:
+    definition: Any other variable
+    unit: EJ/yr
 - Share|Coal:
     definition: Share of Coal in the total primary energy mix
     unit:
diff --git a/tests/test_codelist.py b/tests/test_codelist.py
index 0a833c02..552161f2 100644
--- a/tests/test_codelist.py
+++ b/tests/test_codelist.py
@@ -298,9 +298,16 @@ def test_illegal_char_ignores_external_repo():
     """Check that external repos are excluded from this check."""
     # the config includes illegal characters known to be in common-definitions
     # the test will not raise errors as the check is skipped for external repos
-    DataStructureDefinition(
-        MODULE_TEST_DATA_DIR / "illegal_chars" / "char_in_external_repo" / "definitions"
-    )
+
+    try:
+        dsd = DataStructureDefinition(
+            MODULE_TEST_DATA_DIR
+            / "illegal_chars"
+            / "char_in_external_repo"
+            / "definitions"
+        )
+    finally:
+        clean_up_external_repos(dsd.config.repositories)
 
 
 def test_end_whitespace_fails():
diff --git a/tests/test_core.py b/tests/test_core.py
index ad7abaa8..4d9de9c9 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -126,6 +126,42 @@ def test_region_processing_aggregate():
     assert_iamframe_equal(obs, exp)
 
 
+def test_region_processing_aggregate_wildcard():
+    # Test only the aggregation feature
+    test_df = IamDataFrame(
+        pd.DataFrame(
+            [
+                ["model_a", "scen_a", "region_A", "Primary Energy|1", "EJ/yr", 1, 2],
+                ["model_a", "scen_a", "region_B", "Primary Energy|1", "EJ/yr", 3, 4],
+                ["model_a", "scen_a", "region_A", "Primary Energy|2", "EJ/yr", 5, 6],
+                ["model_a", "scen_a", "region_B", "Primary Energy|2", "EJ/yr", 7, 8],
+            ],
+            columns=IAMC_IDX + [2005, 2010],
+        )
+    )
+    # add_meta(test_df)
+
+    exp = IamDataFrame(
+        pd.DataFrame(
+            [
+                ["model_a", "scen_a", "World", "Primary Energy|1", "EJ/yr", 4, 6],
+                ["model_a", "scen_a", "World", "Primary Energy|2", "EJ/yr", 12, 14],
+            ],
+            columns=IAMC_IDX + [2005, 2010],
+        )
+    )
+    # add_meta(exp)
+    obs = process(
+        test_df,
+        dsd := DataStructureDefinition(TEST_DATA_DIR / "region_processing/dsd"),
+        processor=RegionProcessor.from_directory(
+            TEST_DATA_DIR / "region_processing/aggregate_only", dsd
+        ),
+    )
+
+    assert_iamframe_equal(obs, exp)
+
+
 @pytest.mark.parametrize(
     "directory", ("complete_processing", "complete_processing_list")
 )