I have heard of the USFWS doing some sort of acid etching to recover the #s from very worn/thin bands.

The # to call is 800 327 BAND. That is assuming its a Laurel, MD or USFWS band. One way or the other, they should have some information as to what course of action you can take. But, nice as it would be to hear that ducks story, tread lightly, occasionally with send ins, people don't get their bands back....up to you, but give a call and see what they say.