I can not seem to find a way to kill maggots. Unfortunately something has died under my deck, which I can not get to unless I rip up the deck. I have laid down salt on them and where abouts I feel the deceased is, and for the most part it looks as if the salt might be working, but there are still some wiggling around. Thank you all at Mother Earth News for your help and your time in this matter.
Maggots are the larvae of carrion flies, which are attracted by the smell of anything dead.
But it sounds as if your deck is so close to the soil and to the maggot-infested critter that you'd have a flood of boiled maggots. If you can't get to the cadaver to remove and bury it, just leave them alone. If they continue to crawl up, put several layers of newspaper over the spot and weight it with old boards. In a few weeks, peel or soak it off if you must, and discard. Maggots are a part of Nature's beautiful recycling system.