We used some Merino Wool Rovings bought for just under a fiver on Ebay and some scraps of felt.
We took some of the wool and wound it into ball about 1.5" round.
We then took a tiny bit of liquid soap and some hot water and started to roll the felt ball in our hands - like you would roll a ball of play dough.
We continued doing this, rinsing the ball and our hands under the hot water from time to time and gradually the ball became thicker and smaller.
The balls were then cut in half to make turtle shells and put on a tray outside in the sunshine to dry.
Once the shells had dried we cut bodies from felt scraps and glued the shells on top. We should have embroidered their eyes but instead decided to just mark them with a Promarker pen.
Our 16 finished turtles. A few of the shells weren't perfect but they still look sweet.