Resolving chaos in shared drive

I’m a contractor & each time I get to a new customer site, it’s the same story… there is a shared drive for the office on the company network, and the content is completely out of control. Too much out of date stuff obscuring the important items. Too much chaos in file & directory naming. We don’t have the option of adding any software to the desktop or server. And for some reason, my customers always think I can fix it. Has anyone got any advice?