Over his 20-year career, Trent Dawson, like every plumber, has found a number of prized items covered in sludge in sewer tanks and pipes -- including high school class rings lost more than four decades ago.

But this Ohio plumber went above and beyond the call of duty when he recently employed social media to find the owners of the four rings that have been sitting in his wife's jewlery box for years.

Dawson, of Mansfield, Ohio, was able to track down all four owners -- and met with three of them Wednesday in a ceremony at his Mr. Rooter Plumbing shop, where he reunited them with rings they thought were gone forever.

"I realized that these are sentimental items that have meaning to people," said Dawson, 39. "The rings have first names and years and schools and I knew there’s got to be a way to track them down."

Dawson said the idea first came to him when his 14-year-old daughter asked why her mother's jewlery box had class rings belonging to strangers. 

On Wednesday, Dawson gave Cherie Kissiar, a graduate of Mansfield High School, her 1991 school ring, which he found on the job many years ago. 

Dawson described the meeting with Kissiar as "emotional," saying the ring was especially sentimental to her. 

"The ring was the last thing Cherie's mother bought her before she died of breast cancer," Dawson said. "It meant so much to her, and she actually carried a lot of guilt for losing it."

Connie Keck, a graduate of Black River High School, was reuinited with her 1969 class ring, which was lost sometime in the 1980s and later found by Dawson in a manhole in Lexington, Ohio. The owner of the third ring, class of 1989, lives in Kentucky, and Dawson said he'll be sending the ring home in the mail.

Identifying the owner of the fourth ring was the most challenging of all, Dawson said. The female ring appeared to have the year 1977 with the  initials “R” and “S” engraved in it. But after Dawson's wife took the ring to a jeweler to be cleaned, it was revealed the ring belonged to a graduate from 1972.

Dawson said the ring's rightful owner was identified just three hours after posting its image to Facebook on Wednesday.

"At 4:30 yesterday we got a call," Dawson said. "The lady came last night and picked it up."

Dawson handed over the Mount Vernon High School ring, which was still attached to a gold necklace, found years ago in a sewer and wrapped up in tree roots.