diff --git a/cleanbasestation.py b/cleanbasestation.py
index d402933..911969f 100644
--- a/cleanbasestation.py
+++ b/cleanbasestation.py
@@ -62,14 +62,22 @@ NOT_TITLE_CASE = [
 
 TITLE_CASE_EXCEPTION_RE = re.compile('[0-9]')
 
+def contains_upper_and_lower(s):
+    return any(c.isupper() for c in s) and any(c.islower() for c in s)
+
+
 def title_case(s):
-    if (TITLE_CASE_EXCEPTION_RE.search(s) or
+    if (contains_upper_and_lower(s) or
+        TITLE_CASE_EXCEPTION_RE.search(s) or
         s in NOT_TITLE_CASE or
         (len(s) <= 3 and s not in TITLE_CASE)):
         return s
     else:
         return s.title()
 
+
+# TODO: MCDONNELL -> McDonnell
+
 def fix_type(s):
     if s is not None:
         tokens = [p for p in s.split(' ') if p]