Library Patron question-All she knows was she read it as a child (maybe 1960s) and the main character's name is Cleo

[Jennifer]

Today I got a call from a patron at my library. She's looking for a children's book that she read as a kid. The woman is in her 60's so she probably read it in the late 1950's early 1960's. All she knows was the main character's name was Cleo. She was reminded of this book when she re-read "twig" by Elizabeth Orton Jones (children's fantasy-girl builds a fairy house out of a tomato sauce can). Unfortunately, I'm coming up empty without more information. I'm hoping someone who has read it will remember.

[arratavy]

Cleo's Conquest or Cleo's Misty Rainbowby Lilian C. Garis, maybe. Cleo is also mentioned in The Girl Scouts at Sea Crest; or, The Wig Wag Rescue which is available to preview on Archive.