Is formatting a USB-stick THE way to get rid of viruses and of course the other content of that stick ?

You can reformat it with no partitions and the use file shredder to wipe the free space clean and you should be good to go. shredder writes over all of it three times with 1's and 0's, is free, small, easy to use. and will become a right click menu item to wipe any file you wish on the fly.

www.fileshredder.org