If you are using chemical dyes, you might want to have a different microwave from your family one to process colouring wool and fibre. You can use food colouring which would be a safe option in a family microwave. It is good to talk to people who are familiar with the process so that you get all the tips. The video shows you the process for food colours. Jan 1 sent us a link with very clear instructions from the Virginia Farm Woolworks for if you want to use Landscape dyes or powder dyes. At our dyeing workshop we were using Earth Palette cold dyes because that is easy for beginners but still produces effective dyeing. Little Craft Mouse has a good blog post with a video to show you how to use powder dyes and citric acid. Make sure you protect yourself from stains with rubber gloves and an apron!