I use some construction-grade foil tape to stick them to the bottom, or floor of the cage, and you can put dissipative/electrically-insulative materials atop them, as mentioned in the post above, such as ceramic tiles.
When I put them inside the cage, I always insulate them, to reduce fire hazard, and always, always, always use some kind of thermostat/rheostat/temperature controller.
Ceramic tiles look cool in the right cage, too.
I personally don't use supplemental heat for my corns, as I have the luxury of a snake room, I keep them between 78-82 and they do fabulously. I have 2004's that weigh over 200 grams...
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Jeremy J. Anderson
snakepimp.com
gemstatereptiles.com
Of course it's my opinion, I said it, didn't I?