According to the public health network, generally speaking, the shelf life of soap is about three years. If the soap after opening is exposed to air and water vapor for a long time, the shelf life will be shortened. Soap is a relatively stable substance and can be used for a long time as long as it does not deteriorate during the shelf life. If the soap is not used for a period of time after opening, don't put it directly in the bathroom and expose it to high humidity. You can dry the water on the surface of the soap and store it in a clean box, and then store it in a dry and ventilated environment. Soap can be used for other purposes besides washing clothes. If your bag is not zipped, you can put some soap on it, which will make it smoother.