There's nothing special about a temp file. It's just a file, but in the Temp folder. It's convention that anything added to the Temp folder should only be required as long as the application is open. Any files that need to be retained for future sessions should be stored elsewhere, although that "rule" is not always followed.

You delete a temp file the same way you delete any other file, because they are just like any other file. The System.IO.Path class can give you the path of the Temp folder and then you can delete any file from that folder just like any other file.