Several years ago while standing on asphalt in 100+ degree heat directing traffic for a movie crew the stunt guys taught me a trick for those water retaining neck kerchiefs. The ones that have the crystals sewn into a pouch on them that when wet form a spongey type gel inside.
Take those and put them in a bucket of ice water. Then get a bottle of "Sea Breeze" brand (or similar) astringent facial cleanser and pour it in.
They soak up the ice water and alcohol laden astringent. The alcohol evaporating from the kerchief helps to cool you and the smell of the astringent perks you up (kind of like eucalyptus).