diff --git a/comicapi/genericmetadata.py b/comicapi/genericmetadata.py
index 765ac28..faa3d00 100644
--- a/comicapi/genericmetadata.py
+++ b/comicapi/genericmetadata.py
@@ -211,7 +211,10 @@ class GenericMetadata:
         def assign(cur: str, new: Any) -> None:
             if new is not None:
                 if isinstance(new, str) and len(new) == 0:
-                    setattr(self, cur, None)
+                    if isinstance(getattr(self, cur), (list, set)):
+                        getattr(self, cur).clear()
+                    else:
+                        setattr(self, cur, None)
                 elif isinstance(new, (list, set)) and len(new) == 0:
                     pass
                 else:
@@ -275,6 +278,8 @@ class GenericMetadata:
         assign("_alternate_images", new_md._alternate_images)
 
     def overlay_credits(self, new_credits: list[Credit]) -> None:
+        if isinstance(new_credits, str) and len(new_credits) == 0:
+            self.credits = []
         for c in new_credits:
             primary = bool("primary" in c and c["primary"])
 
diff --git a/tests/ctsettings_test.py b/tests/ctsettings_test.py
new file mode 100644
index 0000000..59d69b0
--- /dev/null
+++ b/tests/ctsettings_test.py
@@ -0,0 +1,26 @@
+from __future__ import annotations
+
+import pytest
+
+import comicapi.genericmetadata
+import comictaggerlib.ctsettings.types
+
+md_strings = (
+    ("", comicapi.genericmetadata.md_test.replace()),
+    ("year=", comicapi.genericmetadata.md_test.replace(year=None)),
+    ("year=2009", comicapi.genericmetadata.md_test.replace(year="2009")),
+    ("series=", comicapi.genericmetadata.md_test.replace(series=None)),
+    ("series_aliases=", comicapi.genericmetadata.md_test.replace(series_aliases=set())),
+    ("black_and_white=", comicapi.genericmetadata.md_test.replace(black_and_white=None)),
+    ("credits=", comicapi.genericmetadata.md_test.replace(credits=[])),
+    ("story_arcs=", comicapi.genericmetadata.md_test.replace(story_arcs=[])),
+)
+
+
+@pytest.mark.parametrize("string,expected", md_strings)
+def test_parse_metadata_from_string(string, expected, md):
+    parsed_md = comictaggerlib.ctsettings.types.parse_metadata_from_string(string)
+
+    md.overlay(parsed_md)
+
+    assert md == expected