Generally, the marinade bag is used for three times. After the fourth time, a new bag is added, and a rope is tied. Every time it is used, an extra rope is tied, so that you can use it several times at a glance.
If you want to use the marinade bag to make brine, you should take the marinade bag out for later use, at the same time, directly heat the water in the pot to boil, and then put it into the marinade bag for cooking. Note that the saltiness of the marinade is related to the amount of water added. It is suggested to add less water when cooking in the early stage, so as to avoid the lack of flavor of the marinade.