Found this online:
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.
Read more : http://www.ehow.com/how_5035187_rech...ilica-gel.html
Hope it helps! And thank you