A plain-knitted square stitched together to form a tube with a fixed piece of string in both ends. Then put a plastic egg inside the tube and sew each end together with the egg inside. Then felt in the washing machine.
1. Plain-knitted squares: for the plastic egg measuring 6cm in diameter, cast on 14 stitches. Knit 40 rows in plain knitting = 10cm. Cast off.
2. For the plastic egg measuring 4cm in diameter, cast on 8 stitches. Knit 30 rows in plain knitting = 8cm. Cast off.
3. Sew the short ends of the square together, forming a tube.
4. Tack a piece of wool at the top and a piece of wool at the bottom of the knitted tube. Put the egg inside the tube.
5. Pull both ends of the pieces of wool tacked at the top to close the tube in one end. Secure. Repeat this at the bottom of the tube.
6. To make a string for hanging, crochet 30 chain stitches for the small egg and 40 chain stitches for the large egg. Felt the egg in the washing machine at 60°. You may pull the egg into shape whilst it is still wet.
An example
This is a photo of eggs in bold colours prior to felting in the washing machine.