There is also steel and gold foil. Neither is great for hats, but they're still options!
They could start wearing those lead vests radiologists put on you when you get an xray alongside the aluminum hats. We know those definitely block radiation at least. Maybe a combo would make it block mind control rays extra good.
If we're in the business of blocking/absorbing signals instead of reflecting them, apparently cesium bromide is a solid choice.
There is also steel and gold foil. Neither is great for hats, but they're still options!
They could start wearing those lead vests radiologists put on you when you get an xray alongside the aluminum hats. We know those definitely block radiation at least. Maybe a combo would make it block mind control rays extra good.
If we're in the business of blocking/absorbing signals instead of reflecting them, apparently cesium bromide is a solid choice.
https://www.photonics.com/Articles/Common_Infrared_Optical_Materials_and_Coatings_A/a25495
"Oh...no, no, no honey, the steel foil hat doesn't go with that outfit, try the gold one."