I am not sure about having used the contact lens cleaner. Most of the time it contains things like boric acid,sodium or potassium chloride, and multiple other conducting preservatives. I recommend that you once more disassemble your iPod and clean it using [http://www.ifixit.com/Wiki/Electronics_Water_Damage|this guide] after that change your battery as well. That way you will not have to worry about it later. Reevaluate for further damage, if any. Hope this helps, good luck.