If a dress, before entering the washing machine drum, were a theatrical comedy, it would certainly be Hamlet. Because the same doubt assails us when it is necessary to read the labels that show the standard symbols for their treatment in the washing machine or not. But how to extricate oneself from lines, dots that seem to be decorations in stylized iron shapes and triangles that are not so far from the nightmare of Bermuda? And bleaching?
Of course, some are completely intuitive, for example that of washing by hand. But if before the iron you find a square with many vertical lines that partially fill it, what do you do? And consider that on average on each label, plus symbol, minus symbol, there are five, starting from washing, through bleaching, ironing and drying. It will therefore be better to follow them to the letter to avoid finding the cover of your favorite pillow as big as a coin purse or your wool sweater as soft as a rock.
Obviously when you take your clothes to a professional laundry, they already know how to treat them but they also follow the instructions on the label to avoid disasters. Here is a pdf with the most common symbols on labels, to be followed to the letter and to be printed and hung in the laundry to avoid divorce.