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Your bills may have become torn while wet, or the water damaged certain features on your money. Thankfully, your bank will replace those bills if they are merely damaged as opposed to mutilated. Damaged bills are those that retain at least 50 percent of its original form, and can be easily identified without any inspection from a currency specialist. If your money is water logged beyond all hope, there's still a chance its full value can be redeemed. The Bureau of Engraving and Printing (BEP) in the Department of Treasury accepts mutilated currency claims, which include wet money. However, there a few requirements that need to be met before placing a claim.  More than 50 percent of the bill must be able to be identifiable as U.S. currency by the BEP. If your wet bills have been severely ripped, the BEP may still accept them if you can provide enough supporting evidence that the missing portions have been destroyed. For those in the United Kingdom, The Bank of England offers a similar service for replacing damaged currency. It's easy for you to further damage your wet currency while you're sending it out. Find a sturdy envelope for your currency, and learn to take extra precautions when packing it.  For wet bills that were rolled, never attempt to unroll or straighten them out. For bills that were straight when water damaged, don't roll them up or add any adhesive if the bills were ripped. Wet currency that's especially frail should be wrapped in cotton or plastic in order to preserve it as much as possible.

Summary:
Go to your local bank. Send your money to the United States Treasury. Know how to properly send in your mutilated currency.