Yep, send the band in, they will etch it (and you will get the band back)! see below
"If you find a bird band with one or more numbers worn off (or if the band number is struck with shot) mail it to the Bird Banding Laboratory to be etched. The number can be retrieved successfully in most cases. Bands are etched using a strong acid solution. The band metal in areas where the number was stamped is weaker and the strong acid solution erodes away more metal where there were numbers, so the actual number is seen when the band is rinsed. The band will be returned to you when the number has been determined if you request it be returned.
To send a band to the Bird Banding Laboratory, tape the band between two pieces of cardboard, wrap the band in padding, or place it in a small box if you want to keep it round. This is very important, as otherwise the band may cut the envelope and be lost in the postal system. Send the band with all the information on how, when, and where you found the band with your address to Bird Banding Laboratory, 12100 Beech Forest Lane, Laurel MD 20708 Attention: Band to Be Etched. If you include a request to return the band, it will be mailed back to you whether we are successful in retrieving a number or not."
Please let us know the results!
Michael L. Schummer
Scientist
Long Point Waterfowl
learn more at www.longpointwaterfowl.org
& visit us on Facebook under Long Point Waterfowl