I have posted in the past about identification of recovered relics, and particularly the use of detecting forums and the wealth of knowledge they provide. Here is yet another example of why it's so important to take the time to understand what it is you're finding. I recently posted a grouping of finds made at an old house site near Swepsonville, NC. They included a pocket knife, two interesting buckles, and this unknown brass item.
I also posted these finds at several of my favorite detecting forums. Two people at the TreasureSpot forum left comments about the unknown brass piece. It was identified as the top hook from a bayonet scabbard! The bayonet hung from a belt, sheathed within a leather scabbard with brass throat and drag. Below is an example of an Enfield bayonet and scabbard from the Ridgeway Civil War Reference Archive.
Without knowing this history or investigating this item, it could easily have been mistaken for a piece of farm trash or unidentifiable, miscellaneous brass. For the novice relic hunters out there, it is always important to save unknown pieces of interest, because it could very well be an important discovery. I hate to imagine my reaction to learning what this piece is once it had already been recycled!