diff --git a/config/vufind/searchspecs.yaml b/config/vufind/searchspecs.yaml
index aec0ae0a2008407d04bf7b80f6ff46d492e23c8c..532a8e3d645d0893e178c1706539027f0648fc5c 100644
--- a/config/vufind/searchspecs.yaml
+++ b/config/vufind/searchspecs.yaml
@@ -502,20 +502,20 @@ CallNumber:
   CustomMunge:
     callnumber_exact:
       # Strip whitespace and quotes:
-      - [preg_replace, '/[ "]/', ""]
+      - [preg_replace, '/[ "]/', '']
       # Escape colons (unescape first to avoid double-escapes):
-      - [preg_replace, "/(\\\:)/", ':']
+      - [preg_replace, '/(\\:)/', ':']
       - [preg_replace, '/:/', '\:']
       # Strip pre-existing trailing asterisks:
-      - [preg_replace, "/\*+$/", ""]
+      - [preg_replace, '/\*+$/', '']
     callnumber_fuzzy:
       # Strip whitespace and quotes:
-      - [preg_replace, '/[ "]/', ""]
+      - [preg_replace, '/[ "]/', '']
       # Escape colons (unescape first to avoid double-escapes):
-      - [preg_replace, "/(\\\:)/", ':']
+      - [preg_replace, '/(\\:)/', ':']
       - [preg_replace, '/:/', '\:']
       # Strip pre-existing trailing asterisks, then add a new one:
-      - [preg_replace, "/\*+$/", ""]
+      - [preg_replace, '/\*+$/', '']
       - [append, "*"]
   QueryFields:
     callnumber-search: