jacques W, now would be a good time to do something:-) before corrosion gets worse. Keep the battery out of your phone and do not try to turn it on.You do want to totally disassemble your phone. Use [http://www.ifixit.com/Device/BlackBerry_Curve_8520#guideList|these guides] to do so. Once it is disassembled, clean every single part, connector and cables ends with +90% isopropyl alcohol. Check [guide|5825|this guide] to see how it is done. It was written for a iPhone 3G but all the points are still valid for your phone as well. Once you have it properly cleaned, '''replace the battery''' check for obvious damage and reassemble your phone. Check for any problems with your phone and address those as they show up. Hope this helps, good luck.