Once the samples have been washed, they are dried and ground. Grinding hair samples is tricky, as they're very elastic. To do this, we use a machine called a ball mill.
Loading wool into a ball mill cartridge
The wool fibres, which are 5-20cm long in the fleece, are cut into ~1cm lengths. Then they are loaded into the steel cartridge with a grinding ball. The machine shakes the cartridge so that the ball crushes the other contents. Note that I'm handing the samples with tweezers: this is partly to make sure they're kept as clean as possible, but mostly because the fibres are very static and stick to my gloves...
And here's the result after a minute or so: wool powder. Like the whole fibres, this is usually static as anything, so it needs really careful handling to stop it jumping about!
Next: weighing into unbelievably tiny capsules in Part 3.