People have often boiled bass strings in water to give them some added life. I’ve tried it a couple of times and it works to a limited degree. You get two or three days of added life and they suddenly go back to their dead state. It's quite strange how quickly it happens.
You should also realize you never want to mix water and metal together if you can help it. There is a much, much better way to clean your bass strings by soaking them denatured alcohol. Read the how to clean bass strings article. Don’t boil your bass strings in water!