Things You'll Need
Microwave safe container
Those nifty packets you find tucked inside your new pair of shoes are filled with silica gel, a granular desiccant that removes moisture, protecting the item from damage. This high-capacity adsorbent is available in loose or packet form and can absorb up to 40 percent of its weight in moisture. Overtime, however, the silica gel can lose its moisture-removing power and become ineffective. When this occurs, don't throw the silica gel out: recharge or dry it with heat so you can continue to use it.
Preheat an oven to 275 degrees Fahrenheit. Line a baking sheet with aluminum foil.
Lay the silica gel packets flat on the foil-lined baking sheet. For loose silica gel, spread the granules in a layer no more than 2 inches thick on the foil-lined baking sheet.
Place the baking sheet inside the preheated oven and bake for several hours. The amount of time varies between 1 to 12 hours depending on the thickness of the silica gel. A good general rule of thumb is baking for 1 ½ hours for every 30 ounces of silica gel.
Remove the baking sheet from the oven. Let the silica gel cool to room temperature on the baking sheet.
Store the cooled silica gel packet in an airtight container until you're ready to use it.
Place the silica gel in a microwave safe container. Set the container inside the microwave.
Heat the silica gel for three to five minutes on medium to medium high.
Examine the silica gel for color change, which will occur when it is recharged or dry. If it is not dry, stir with a spoon and place back into the microwave for an additional three to five minutes.
Continue checking it for color change and microwaving for three to five minutes until the gel is dry. Let the silica gel cool to room temperature in the microwave-safe container.
Wear an oven mitt when removing the baking sheet from the oven.
Never handle silica gel immediately after drying; it can get very hot in the oven or microwave.