Many files in $APPLCSF/out

There's many files in $APPLCSF/out which I don't think is a new issue, but I'm requerying the question to get the best answer to this problem that can be applied onto a 12.1.3 environment in 2020. I don't want to "remove all files older than X days" because that is not really a functional solution. I want to remove the MOST UNNECESSARY files in this directory. There's no way all of these files are important, so, which ones do I remove, which not. - Keep in mind: all of this while the Conucurrent Manager is active. --- Thanks