Why is my iPhone turning on just sometimes?

Yerudo. "as with an immersion, the importance is to not turn it on, or trying to sync/charge it, as this may increase the likelihood of shortcircuiting any components. Remove the battery, and disassemble it right down to the logic board. Clean everything with isopropyl alcohol (90%+) and a soft brush, including all connectors and cable ends. Check for any burned or missing components. You may have to repeat this step a couple of times. Once it is cleaned, reassemble it and replace the battery, then reevaluate for any real damage. Yes, it is possible that all of your problems originate from the battery, but you do want to avoid any failure later on. So, clean it very well. Hope this helps, good luck."