I take mine out to the flower boxes in the back yard. I lightly tap them with a hammer and knock off the corrosion and scrape them on the concrete to knock off the fine stuff. Banks return coin currency to the mint, for evaluation. After rinsing my coins, I dump them into the coin machine at my credit union. Yesterday it rejected all the corroded pennies though. I will roll them up and deposit them into my account. They are still legal currency and you WORKED HARD FOR THEM, you may as well get paid for them, RIGHT? OBTW, sometimes when I hammer off the corrosion on heavily corroded coins, they come apart, but I very rarely lose one that way, savvy? If you roll them and deposit them, there should be no issue, they are legal tender, get paid!