Monika, just like any other phone, you will have to clean it. If you do not, then you will have corrosion set it. Disassemble your phone, [https://www.youtube.com/watch?v=sXZqIjtFoAU|here is] a decent video that will show you how to do that. Clean all the parts with 90%+ isopropyl alcohol. After that replace the battery and reassemble your phone and re-evaluate for any residual damage. Hope this helps, good luck.