In our experience thorough preparation of the fleece before spinning usually results in a better yarn. Once the fleece is washed and dry it could be spun. Alternatively it can be carded, the fibres combed and easier to manage.
However, depending on the state of the fleece you started with, after washing there can still be bits of straw and dirt mixed in with the fibres and not all of these come out in the carding so after doing a bit of research online we built a picker.
The picker looks similar to a medieval torture device and could probably cause a fair bit of pain if you got your hand stuck in it.
Armed with just a few images from videos on YouTube, some old scraps of wood and a bucket of nails, after a week of work we managed to produce our own machine.
To test it we grabbed a fleece and pushed it through the wicked looking teeth.
The arm swung back and forth separating the fibres and allowing the bits of interwoven dirt to fall out.
After two goes we were left with cleaner, fluffy fleece which looked ready for carding.
It wasn’t 100% dirt free, there were still some bits stuck in there but it was so much better.