Is aluminium foil good enough?
How many layers should I use?
Should I make the whole hat out of foil or wrap a hat with foil?
Wouldn't a helmet be better?
Maybe some sort of composite with a fine copper mesh?
Did I tell you guys about the global conspiracy to form one world government by inventing global warming? Today was cooler than average! Cooler!
To quote from a great work of fiction by P.D. Eastman "Do you like my hat?"