If you are so concerned with security dont use IE. Use a Portable Firefox, so all cache files are inside Firefox folder and wipe the folder after use. (Use a new copy each time)
If you put the Portable Firefox inside an encrypted drive you dont have to wipe and lost cache files every time (they make navigation faster).
Remember that data is stored by the system in the paging file and be recovered with special tools. So you may need some tools to wipe it.
http://portableapps.com/apps/internet/firefox_portablehttps://www.steganos.com/us/products/data-security/safe/overview/http://www.jetico.com/wiping-bcwipe