Dear Rabbi Simon
I want to take up embroidery and I am particularly interested in crewel work which is traditionally made from wool on a cloth of linen or one with some linen content. Given this is sha’atnez I don’t think I can do this – I’m pretty sure I can’t gain any benefit from the use of wool and linen even if not worn?
The prohibition of shaatnez is limited to wearing, or any use which provides warmth. This includes a blanket, as well as a pillowcase, mattress or a sofa. Even a curtain or tablecloth may provide warmth under certain circumstances and should therefore be avoided. However a wall-hanging or tapestry made of sha’atnez would be allowed.
For this reason there may be forms of crewel work which are permissible as a hobby or craft. However you would need to be careful to avoid draping the fabric over your lap, for example, in the course of your handiwork.
I hope this is helpful.
Rabbi Rashi Simon