Well, I agree with Techknight, the drive is junk if there are grooves eteched into the platter. There's a chance it still sort of works, but it'll never be reliable or trustworthy, and there are likely going to be many errors in formatting it.

Maybe to prevent this in the future, try carefully opening up the drives and lifting the head off the platter and blowing, as you did with this drive? If you do that, it will at least reduce the possibility some.

I should probably check out some of my drives, but I think at least some of them will probably still work, I hope.

Good luck with the rest of your drives!

c