How to place all .au files generated into flash disk?

After recording from old cassatte tapes, there are a lot temporary “au” files created and being stored into a audio v2.0 temporary folder which I could not find where is this temporary “au” files located under a temporary folder of C: drive of my laptop with Microsoft Window 7 and which will occupy a lot spaces of C:, may be 1 gb spaces for two hour recording. When I colse Audacity V2.0 after I save it into a mp3 file and click “Not Save” button, all these temporary “au” files will be deleted and so they will not occupy huge spaces on C: of hard disk where Microsoft window 7 was installed. Because performing a lot recording in 6 months period and a lot temporary “au” files were being created and deleted on computer’s hard disk which causing my hard disk is out of work (died). Therefore, I want to place these temporary “au” files on a flash drive with 8 gb size, cost only $4, while recording so that I do not need worry to make any damages on my hard disk. HOW COULD I SAVE these TEMPORARY “au” files ONTO A FLASH DRIVE before I start recording under Audacity V2.0? I need use Audacity v2.0 its removing noise option to remove a lot noise from the cassatte tapes before converting and saving to an MP3 file. Sorry, I use bold font because of my vision problem. I do not know how to removing bold font after my first posting. Any internet radio stations have radio reading to read best selling books, portry, drama in England, UK?

Edit > Preferences > Directories > Set Temp Directory and Drive (on Windows and Linux)