Clementines are such a perfect size for making clove balls as you can fill the whole fruit with the cloves and it doesn't take forever...But it does require some patience. Don't place the cloves too near each other as the clementine will shrink as it dries. Clove is a natural preservative so this will last for several years.
The above picture is freshly stuck clementines, I let them dry on a plate for several weeks to a month. They will shrink and turn brown and become very fragrant. Once they are dried you can tie a ribbon around them and hang them up. If you do hang them before they are dried, the ribbon will get too loose and fall off.
Clove balls are also known as Pomanders, the term goes way back to the middle ages when people carried around balls of just about anything that smelled good to ward off sickness or maybe because they really missed deodorant. You can get very fancy with decorating your clove ball if you like, but I say the more cloves the better!