The swords that the Hobbits got from the Barrow Downs-downs were apparently magical in some way: in "The Departure of Boromir", Aragorn says this of Merry and Pippin's blades: Doubtless the Orcs despoiled them, but feared to keep the knives, knowing them for what they are: work of Westernesse, wound about with spells for the bane of Mordor.
Doubtless the Orcs despoiled them, but feared to keep the knives, knowing them for what they are: work of Westernesse, wound about with spells for the bane of Mordor.
There are several reasons to believe that the barrow bladesBarrow-blades were particularly harmful to the NazgulNazgûl. A major piece of evidence is the effect of Merry's blade on the Witch King (during-king during the Battle of the Pelennor Fields. It was enchanted with the power to harm the Witch-king of Angmar himself).
We know almost nothing about whether the barrow bladesBarrow-blades had any special effect on other evil creatures. In "Flotsam and Jetsam", Merry says that UglukUglúk (leader of the Uruk-hai band) took the swords but then "threw the things away as if they burned him." http://stason.org/TULARC/education-books/tolkien-newsgroups/45-Were-the-barrow-blades-magical-In-what-way-Tolkien.html#.UXlaMXfn_mI#ixzz2RUfmq0BO
(Details of question quoted from here.)
With that said, how did the Hobbits get their Barrow blades-blades back if the Uruks threw them away after Merry and Pippin were captured?