pva_src directories and their contents

Windchill 9.1 with WF5.0 on Windows

In an effort to reclaim disk space, I came across a lot of directories in the /windows/temp directory.   The directories are named pva_src.xx  (xx are sequential numbers).   In these directories are many .xpr files as well as some .prt files.   I believe these directories are left over temporary working files for the product view publisher engine/process.    I am about to delete these directories if they are more than a week old.   Any potential problems that anyone is aware of?

Thanks

Michael in Kansas