Cure for crashing iPhone

My iPhone kept crashing. If I left it on overnight it would invariably crash by morning and drain the battery in the process. I tried all the cures suggested on the Internet, including wiping the phone and reinstalling everything from scratch. That worked for a while then it started crashing again. I tried shutting it down overnight, but it still crashed the same. So then I tried shutting it down AND wrapping it in aluminium foil. And hey presto -- it woke up the next morning and the battery was fine. So this tells me that there is some communication going on between even a 'shut down' iPhone and the service provider, since radio waves can't penetrate alfoil. Also that there is some kind of broken connection that it tries to re-establish overnight that fails repeatedly until it runs out of power. Miraculously, the foil also stopped it crashing -- for a while. So those broken connections appear to be marked as 'stale' and it doesn't try to remake them, though eventually new ones appear. So if you have the same problem it can't hurt to try the same remedy that worked for me -- shutting it down overnight and wrapping it in alfoil. It's a lot easier than reinstalling the software.