When I work the bases in high heat and humidity, between innings I have the trainer bring me a half a cup of crushed ice.  I take off my hat, dump the ice in the hat, put the hat back on, and it keeps me cool for a good two innings.  As the ice melts the water runs down the back of my neck which helps the cooling process.  Nobody notices since it just looks like I'm sweating - which I am anyway!  Try it -
JJ
Patent pending 
