Iphone 4 home button/reset help

My phone has previously had water damage, but after drying it out and doing a hard reset it was fine. My iphone 4 home button stopped working recently which wasn/t an issue until my phone crashed yesterday and I am unable to do a hard reset. It is not responding at all nor is it registring on itunes. I took it into the genius bar but as it has previously had water damage they are unable to help me. I can't afford the £110 pounds to replace it so was wondering is there anyway to do a reset/restore the phone without having to use the home button. Thanks in advance 🙂