Originally Posted by Diver Dan
How did the backing look? Maybe it isn't mildew. Could be something else if none of the other stuff in the same spot had a problem. Most curious.
A couple of small spots but mostly clean. I don't think I ever had that reel all the way out into the backing. If it's not mildew it might be some sort of mold or algae that was in the water that the line picked up. I think I did rinse the whole thing in fresh water after I used it, though.
My working hypothesis is that I must have put the reel back in its neoprene case before it had fully dried out. Then I put the case in a duffel bag with the rest of my gear to bring it home, and it sat there for a few months without much air circulation. I assume, but maybe I'm wrong, that whether it is mildew or something else doesn't make a difference in how to restore the line.