I love these bandanas. I bought the 4 pack for my family. My husband is a Mason and in the Hawaiian Sun during the peak hours he can get migraines from the heat. This works WONDERS! It's amazing how quickly you cool down from simply cooling the back of your neck.  There are a few tricks to the bandanas before you start using them. I soak mine for at least 30 minutes in cold tap water to get the gels activated. I gently squeeze out the excess water. For the first activation you'll find that the bandana is a little slimy from the gel. So, after getting the excess water out, I soaked it again. This time in mild soapy water then rinsed it off again. It took about 3 soaks to get the slimy feeling to go away.  Then before actually using it, I hung them out in the sun and air to dry completely until I was ready to use them.

This product is meant to remain moist all the time while using. If you perspire heavily, this bandana will begin to smell.  I rotate the bandanas. Wash the used one in soapy water then hang to dry completely. When completely dry and not in use, store them in the (dry ) laundry detergent box.  The material and gels will take on the smell of the detergent. When I'm ready to use them, I rinse them off completely (the detergent will stick to the material), soak and use. If you don't want to store it in your detergent box, you could always wrap it in your dryer sheet and store for later use. This way you always have a fresh and clean bandana to use.
Try not to oversoak the gels. The longer you soak them, the more water they absorb and it can get tight in there. I've had some gel seep out through the stitching. Don't wring out  the bandana or that will also squeeze the gel out as well.

For extremely hot days I put it in the fridge for a bit to cool it down even more. I carry one in a Ziploc bag in my bag when I know I'll be out all day.

Hope this info helps!