Q: I sometimes get confused with all the types of threads that are available, when do you use what type of thread? Q: I sometimes get confused with all the types of threads that are available, when do you use what type of thread? A: A good guideline is to use thread that is similar to the fabrics you are sewing. Cotton threads on cotton fabrics. Poly thread on synthetic fabrics. Silk threads on silk fabrics. Rayon and poly metrosine threads are both used for machine sewing and machine embroidery, both come in a shine and low gloss finish, just remember that rayon threads will break down if exposed to sunlight for prolonged periods. Spools of thread will dry out over time, so if you are having problems with your thread try a little thread conditioner or put it in the freezer for a week or so to see if that will help. A good quality thread will make your sewing project much easier when you are not dealing with threads breaking and shredding while you are sewing. Tags: Array