yazafoo, first thing to do is to '''not''' continue to try to start the phone. you will have to disassemble it, use [http://www.ifixit.com/Device/iPhone_4_Verizon#guideList|this guide] to show you how. After that, clean it using [guide|4892|this guide.] It was written for a 3G but all of the cleaning will still apply to your phone as well. When you do clean it make sure that you use a high grade isopropyl alcohol and that you are careful with any brushing etc. so you do not knock any components off the logic board. Once '''properly''' cleaned, replace the battery and reassemble the phone, reevaluate for any damage. You '''may''' have to get a new display due to the oil. Hope this helps, good luck.