how can i repair my nokia 6230?

You haven't messed anything up!.. Liquid damage will slowly kill a phone no matter how well you dry it or think you fixed it!.. 80% of our liquid damge repairs normally work for a short time .. and then the phone dies,.. eventually!.. I hope you have insurance fella?..
if you have a reputable phone repairers near by ask them if they will clean it in a sonic bath!.. if they look at you "gone out" when you say sonic bath....LEAVE!

Sjcomms
February 2007