How to make easy felted balls

Felted balls are a common natural toy made of wool roving.  They're soft, beautiful and retain all of the benefits of wool.  I made my own version of these balls yesterday for our afternoon art project.  Something so simple but lovely to hold.  We call these "treasure balls". 

Supplies:
100% wool roving yarn (or any wool yarn but I like "roving" because it felts better)
Jingle bells (I prefer a medium to large size)
Pantyhose
Detergent and/or dish soap
Vinegar

Procedure:
1. Wind the wool roving yarn firmly around the jingle bell until you have a ball in the size and shape you like.  Repeat this for as many balls as you wish to make.
2.  Take a pantyhose leg and stuff one ball inside and tie it off with a piece of yarn to hold it's shape in the washing machine.  Repeat this for as many balls as you're making.  Each ball needs to be tied off individually so that it looks like a strand of pearls, not a bean pod.  The end result might look like a caterpillar.
3.  Wash in the washing machine with detergent for a few hot/cold cycles.
4.  If this isn't enough to felt it, what I did was soak and rub the balls in one bowl of hot water with dish soap and then alternate with a bowl of ice cold water.  I found it easier to put the 2 bowls in the kitchen sink since you'll have splashes. Alternate washing and aggitating the balls a few times.
5.  Rinse in white vinegar and then rinse it one last time in water.
6.  Remove the balls from the pantyhose (or you can remove them immediately after they come out of the washing machine) and let them dry.  The pantyhose will be stuck to the balls but just peel it off or cut as much of the pantyhose off with scissors.  It might be a little fuzzy, but it'll come off.
NOTE:  Feel free to mix pieces of yarn together to create different color combinations.  Or, try making an orange felt ball to be a pretend orange, or a red one for an apple, or a bunch of little purple ones to create a bunch of grapes.  They can be a model solar system, snowmen, beads for jewelry, or garlands for decorating. With the jingle bell inside they make perfect cat toys or the larger sized balls can be used for baby toys. I get a lot of inspiration from Etsy or just Google images of it.