Once I had finished spinning on my spindle ( usually more than shown on the photo) I slide the cops off and instead on winding into two two balls to ply I placed them to soak in cold water.
In the meantime make up your dyes, I use easy acid dyes which just need hot water to dissolve the powder, using all the necessary health precautions including ventilation, gloves and mask. Fill half a jam jar with the first colour and half a jar with the second. For the first trial I used blue and yellow.
After soaking for 30 mins or so ( you really want all the yarn to be wet) gently squeeze out any excess water. Place the cop in the jam jar so the dye comes almost half way up and leave to soak for a few mins, then turn the cop upside down and place in the next jam jar.
Once steamed,leave to go cold then rinse in cold water and leave to dry on an old towel,
Other colour results......using red, grey, blue