Workbooks – privacy and storage

I’m looking for ideas around the privacy and storage of my used SCS workbooks. When I do my thought downloads and models, I write some extremely personal stuff that I would not like to have read by anyone. I keep going back and forth between leaving my workbooks out on my desk where I can see them versus hiding them away for privacy. Also, is it beneficial to keep workbooks from prior months? I feel like it is but then I again think of the privacy issue. Thanks for your advice!