Recheck bad sectors reported by smartctl

Hi All

I got a warning that my disk containing my /home partition was going to fail within 24 hours. I"ve been backing up all my important data to another partition. The "Reallocated_Sector_Ct" (count of bad sectors I presume) was around 3000 when I first saw it, it's steadly risen to 4004 over the day. However, I remembered I put my PC case on it's side a few weeks ago, and left it that way. I turned it back upright, and the "Reallocated_Sector_Ct" has not increased from 4004, even though I'm still using the computer and it's currently tarring most of my home directory. Perhaps my hard drive is just temperamental about being on its side? I know that's not great but at least I was hoping I don't have to panic as much. I wanted to get smartctl to recheck the bad sectors (and ideally the bad sectors only) and mark them as good again if they're okay. How can I do that?

I'm running Debian if that makes a difference.