Didn't want to hijack the thread below. I have marks on my propshaft(86 merc 60), not enough to catch a fingernail, 3 lines in the seal area that you can see it the right light. The shaft area where the seals seat is clearly rubbed, probably worn a little but not something I can tell by eye. Can I get these marks out with 400 grit emery cloth or is the shaft done for?