A dress snag occurs when one or more threads are pulled away from the cloth's pattern, causing what can look like a run or bunching of the fabric. If this happens to one of your favourite pieces of clothing, do not immediately assume that you have to throw it out, or donate it to the needy. There are a number of ways that you can remove a dress snag in your very own home.
If you're working with a smooth fabric such as cotton blends or satin, you can attempt to minimise the snag by using your fingers to move the fabric side to side, urging the threads back into place. Working your hands in a back and forth motion encourages the snag to smooth out and head in the direction of the rest of the clothes pattern. Sometimes this is successful, but one small piece of lose thread will still stick out. If this happens to you, try and pull the thread under the fabric instead of cutting it, which can end up creating a hole in the dress.
Hiding a snag in a woven or woollen garment, such as a knit sweater dress, is often easy to do, because there are a number of small holes in which you can pull threads through without making it look too conspicuous. If one of your woven pieces comes up with a snag, simply use a needle, crochet hook, or your fingers to pull the thread to the wrong side of the garment, tie it off in a small knot, and use clear nail polish on the thread to prevent it from fraying.
Hiding a Snag
If you cannot fix a snag with the above methods, and the snag is near a hem (such as the top or bottom of the dress, or near the sleeves or a pocket), you may be able to rehem the garment to hide the snag. You can do this by hand, or with a sewing machine, or get a friend or relative who is proficient in sewing to do it for you. Another option is to add a pocket or embellishment to the garment.
When All Else Fails
When none of these options work for you, it is time to take it to a professional seamstress. The seamstress will either be able to fix the snag without causing any further damage to your dress, or at the very least minimise the snag so that it is not noticeable to anyone who does not already know it is there. This may cost you a bit out of pocket, but it will still be less expensive than having to replace the item.