[FONT=Comic Sans MS][COLOR=teal]A few years ago I won a lot of cone yarn on eBay. Unfortunately, when it arrived I discovered it was ‘industrial’ yarn which is about the thickness of heavy thread. I recently started plying this cone yarn into a knittable thickness and it’s working very well. I now have some skeins of lovely soft yarn. Now for my question. I know that after I spin wool I need to wash and soak it in hot soapy water but these skeins aren’t all wool. Some are 100% acrylic some are 75% cotton/25% acrylic, some are 100% cotton and some are 75%wool/25% acrylic. After plying do I need to wash and soak the skeins to set the twist or is that only reserved for newly spun wool?[/COLOR][/FONT]
I think it depends – when you hang the skein, does it twist back on itself? If it does, and you knit with it as-is, it will likely bias because of the added twist. You may want to try washing it and then thwacking it around for a bit to try to relax the extra twist and balance the yarn.
Another way to remedy this would be to make a cabled yarn – ply two strands together in one direction, then ply two strands of that yarn together in the other direction, hopefully yielding a balanced 4-ply.