Free Mac tool to rename files for Windows compatibility?

I don't normally support apple computers. We have a macbook that was used by a contractor. We want to copy the content up to the cloud but have the standard windows restrictions - e.g. no space invader icons for file names and nothing beyond 250 or so characters in length.

Is there a free tool I can run on the mac that will find and help me rename those files that don't meet those restrictions you'd recommend?

Thanks