Dopped my Iphone in tea in August?

Hey everyone, I dropped me iphone on a warm mug or tea in August, it is now January, it has dried enough to swich on but it will randomly turn off also when i take out my charger it will turn off. Im going to get it fixed at a shop, what would i need for it to work perfetly again like a new battery ir what??? Thank you, its and iphone 4 by the way :)