tin foil or cardboard
i had this issue i live in alaska so lol..
if u use foil thats on someone else to explain but the card board is easy
take a box n cut just big enough for the light/lights to fit in then leave about an inch in the middle for air flow this will lock heat and humidity it
also i use sphagnum moss in a plastic bowl under my snakes light to make it humid
if u dont have this then im sure wet paper towel would work <?