Guavas should be stored *with* their skin intact for pulp use. The skin contains valuable nutrients and flavor, and helps protect the fruit from oxidation and spoilage during storage.
When preparing guavas for pulp, the best practice is to wash them thoroughly and then store them whole, with the skin on. The skin of the guava is rich in vitamins, antioxidants, and fiber, all of which contribute to the nutritional value and flavor profile of the pulp. Removing the skin before storage exposes the flesh to air, leading to oxidation and a loss of flavor and nutrients. Storing the guavas whole also helps to maintain their moisture content and prevent them from drying out. When you're ready to make the pulp, you can then process the entire fruit, including the skin and seeds (if desired), for maximum flavor and nutritional benefit. If you prefer a smoother pulp, you can strain it after blending.
To extend the shelf life of your guavas before making pulp, store them in the refrigerator. Place them in a perforated plastic bag to allow for some air circulation, which helps prevent moisture buildup and mold growth. This can keep them fresh for several days longer than storing them at room temperature.