Stephanie, there's a cup of tea here for ya :)
Stephanie has brought these vetiver filled fiber balls to my attention and wondered if I had any hints for making them with leftover yarn. Well, yes and no.
Vetiver is an Asian grass mostly used for perfume. It's a major ingredient in many fragrances. The ones one that website look like their wrapped in cotton thread. I don't really know how to make those.
But there is a way to make wool felted balls that look like those. All you need is some fleece or roving, wool yarn leftovers, an old cheapo pantyhose, some warm water and soap.
Take the fleece and pull it into bits. Take a few pieces into your palm and start layering, one fleece layer onto another into a ball of fleece. Throw that into the toe of the pantyhose. Tie a knot so it's secure and does have any room to move about.
Repeat with the rest of the fleece. You'll end up with a pantyhose garland ;)
You can add bits of leftover yarn into the outer layers as a bit of decoration or not. It's up to you.
Toss it into a pillowcase. Tie up the top of the pillowcase. Toss the whole kit and kaboodle into the washing machine with hottest water and shortest cycle.
Then toss it into the dryer. Once dry, cut them out of the pantyhose.
The only thing you have to worry about is make sure you're using feltable fleece and roving. There are some sheeps' wool that don't fleece very well. You can buy dyed and undyed fleece from craft stores, LYS or call up your local sheep farmer.
Also, from what I hear and have read, stick with the cheapo saggy pantyhose. The fancy schmancy ones have something in them that somehow impedes the whole felting process.
You can use felted balls for kitty toys, pincushions, for decoration or make little ones by hand and string them together to make a necklace or bracelet. You can make a kitty toy that will drive everybody crazy by sticking a bell inside a lacerated tennis ball and felting the outside of the ball. Felting can be done in a sink of warm soapy water. Just simply rub and squeeze it until the wool starts felting.