Hi Mara. When I make stripes in the round, I usually just carry the unused color up every row until I need to make the change. At the beginning of each row I just twist the yarns so that the unused yarn isn't loose at the back. It's almost as if it's been stitched into the fabric. I used that technique when doing these legwarmers and it worked out very well.

Here is a link that might be useful: {{gwi:1575744}}