AFAIK, you can't change the folder where the AME stores its temp
projects. You can, however, put a shortcut to that folder on your
Desktop or anywhere else that you want. Whenever you feel like it, open
the folder and delete the temp projects.
You should also clean out the Media Cache Database on a regular basis.
In Pr, go to Edit | Preferences | Media and click on the clean button.
You can also set up a Temp folder on C:\Temp or any other drive and then go to System properties > Environment Variables and in the window select Temp variable and Edit value to your likeness and do it for both variables. Also edit System variables for temp folders as well. Now it will be some where you can easy access it and clean that folder when needed.
I sort of doubt that will control an Adobe generated TEMP file. But I am willing to be proven wrong if someone tries it and is successfull.
There is another item to help when you go to Jeff's suggested "Edit | Preferences | Media" you can check "Save Media Cache file next to originals when possible" This will keep them off the C: drive.
It will not control generated Temp file by AME instead AME will use the default windows Temp folder location and it will store its temp there. And basically you are changing Windows default location for Temp folder. So once it is changed all programs will store temp files in that location. I do this on all of my PCs so that I have ease of access to it just for cleaning purposes.
Preferences are designed for scratch and peak files but not for AME temp file that is created just for rendering. That particular file is using windows default Temp location folder.