About 15 years ago, we helped my MIL buy a used car. We cleaned it out for her, and found papers on the previous owner, who we realized was a teacher that our sons had in grade school. DH removed the floor mats to replace them, and found a diamond ring wedged underneath. We contacted him, and it turned out to be his wife's engagement ring, which had been lost several years before that! He said they had "torn the car apart" looking for it!