I have a huge respect for those actors willing to wear heavy costume for several hours in a very poorly air conditioned suit/environment. What I am going to suggest is something I have tried with success to keep cool. This is a roll-on ice product sold at drug stores. It's main purpose is to keep your feet cold when they get hot. But I tried it under a heavy costume. I kept cooler that I normally would have been overly hot. Give this a shot, you will be glad you did.

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