Well, Sam and Dean have run up against these suckers a couple, three times. Picked up a few tricks – enough to slow them down a hair, at least.
Though unnamed in the series "reaper traps" are used much in the same way as devil's traps are for demons, in that they are used to immobilize reapers. Once a reaper is caught in one they are rendered powerless and completely vulnerable. The traps also appear to be Enochian in origin.
The first and only time Sam and Dean encounter a reaper trap is during a case in Greybull, Wyoming where people have stopped dying. Sam and Dean decide to astral project in order to speak with the last person to die, Cole Griffith, it is then they learn that the town's reaper was abducted by demon smoke, and soon witness the same happen to Tessa after she arrives. They arrive at the town's funeral home to find Tessa and the other reaper lying in a reaper trap, Sam and Dean take the fight to the demon standing guard, but are quickly trapped behind an iron chain. Just as they are trapped, Alastair arrives to explain he is breaking one of the 66 Seals - specifically a seal that will be broken if two reapers are killed under a solstice moon. He is successful in killing the town's original reaper, but is stopped when Sam and Dean use telekinesis to bring down a chandelier and break the trap, allowing Tessa to escape along with the Winchesters.
While Bobby lies in a coma, within his subconscious he is being pursued by a reaper. Having remembered Sam and Dean's previous encounters with reapers, Bobby cooks up a plan to slow his reaper down long enough for him to find an exit out of his coma. Bobby and Rufus go about collecting materials to summon the reaper, of which includes: a crucifix, gold ore, hemlock, mace and blood, among other unknown ingredients. After painting the trap on the floor, the ingredients are mixed and set a flame as Bobby recites the phrase:
O theristis, kaleo se kai deo.
Summoning the reaper and effectively trapping him within Bobby's subconscious, however it is only temporary as the bullet is slowly killing Bobby's brain cells and will eventually reach the reaper once Bobby's office disappears, thus freeing him to continue his pursuit of Bobby.