)
There is a mitzva to refrain from wearing clothes which contain both wool and linen, as we read, “You shall not wear a mixture (shatnez) of wool and linen together” (Deuteronomy 22:11). Thanks to the increasing availability of cotton and other synthetic materials, clothing manufacturers now use very little wool or linen. In fact, they total only about one percent of the materials used in clothing production. Therefore, the likelihood of buying anything with shatnez is very low, so it is sufficient to check clothing labels to comply with this law. As long as the label does not list both linen and wool, the clothing may be worn. Only very expensive wool suits are still a concern. If such a suit is bought from a seller known to be honest and who can attest that it does not contain linen, the suit may be worn. Otherwise, the suit must be checked in a special shatnez laboratory.
