RB has a spot in the Audio Prefs for where those temp files are located (and they are flushed when RB is closed). I use a separate drive for the recording/temp folder. Actually I use a separate partition with one folder..
It's called Audio Temp Directory and it is where temp files and incoming audio get handled. Until that session ends the temp files remain.

Create a new empty folder in Windows
Assign it as Audio Temp Directory in Audio Prefs
Open a project with edits (or do a couple edits), check folder (should have files)
Close RB
Check folder (no files)


I do not work here, but the benefits are still awesome
Make your sound your own!