Reg Mitchell answered on March 1, 2007, A:If you found this answer useful, please consider making a small donation to science.ca.
First of all do not worry too much. The mix is not particulary toxic, just strongly alkaline like Drano, so things need to be well washed, but that's about it. Alkaline batteries contain zinc, manganese dioxide and Potassium hydroxide. The last one is similar to lye or sodium hydroxide, the main ingredient of Drano. Potassium hydroxide is corrosive and since it absorbs carbon dioxide from the air, it becomes less corrosive with time. In any case, it is easily neutralised with a bit of vinegar. Use rubber gloves and wash anything that was touched by the contents of the batteries with a damp cloth several times, or better yet, a cloth dampened with vinegar, then with water on another cloth, then dry. That should fix the problem. Any other objects can be washed (just as though you are washing the dishes) but paper may or may not be salvagable.