I'm not sure how much good old exams would be ... the body of knowledge and the pool of test questions for
all of the ASQ certifications are reviewed and refreshed about every five years or so. Each test is different because the questions are drawn at random from the pool. Also, the whole quality engineering profession has changed so much since the early 1960's that the old exams would not even cover a lot of the current topics, and may even be just plain wrong on others!
I agree with Bill Ryan - the CQE Primer by Bill Wortman (Quality Council of Indiana,
www.qualitycouncil.com) is excellent. (It's what I used a dozen years ago!)
Other resources would be topical searches of The Cove (there's a wealth of good stuff here) and some of the references ASQ lists with the CQE body of knowledge. One I personally recommend is
Quality Planning and Analysis by Juran and Gryna.