For some reason I tried it recently, as my work file drive was fuller than I liked and I knew I had some redundancies.
It wiped everything. Every single audio file for every project.
Thanks to EaseUS ToDo, I could restore a backup from the previous day.
I will never attempt to use Clean Audio Files again unless it is significantly revamped. Using Save As to move projects to a temporary location, deleting the original and moving the Save As files back to original location works. It is very tedious when you have a lot of projects, but you keep your work.