Here is from the US Treasury website. I think the cost of sending the coins in would probably equal the actual coins value.
I have some coins that were damaged. Where can I redeem them?
The Treasury Department has prescribed regulations regarding uncurrent and mutilated coins.
Uncurrent coins are whole, but are worn or reduced in weight by natural abrasion. They are easily recognizable as to genuineness and denomination, and they are such that coin sorting and counting machines will accept them. Merchants and commercial banks will generally accept or refuse these coins at their discretion. However, Federal Reserve Banks and branches handle the redemption of uncurrent coins. Uncurrent coins are replaced with new coins of the same denomination by the Federal Reserve Banks, then forwarded to the United States Mint.
Mutilated coins, on the other hand, are coins that are bent, broken, not whole, or fused or melted together. The United States Mint is the only place that handles redemption of mutilated coins, and they should be sent to:
U.S. Mint at Post Office Box 400, Philadelphia, PA 19106. Phone: (215) 408-0203
All uncurrent or mutilated coins received by the Mint are melted, and the metal is shipped to a fabricator to be recycled in the manufacture of coinage strips.