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Redirects are a funny old thing, and a source of much frustration for many. I asked John Mueller about this last year and his response was basically, "be patient". There are occasions where a reversed redirect can see an almost immediate change, then other times it seemingly never happens - in the long run, it probably will though. Just don't go changing back and forth too quickly because this is likely to cause you extra headaches. -Andy

I'd still disavow these because you never know when those dead domains may come back online again. There is no disadvantage to disavowing spammy directories that no longer exist other than the time it takes to do so. With that said, however, it's not likely to make a significant difference to your rankings whether you leave these or disavow them.  In the past, these spammy domains had the possibility of causing your site to be suppressed by the Penguin algorithm. But when Google released Penguin 4.0 in September of 2016, Penguin no longer demotes. It simply stops counting any link metrics from spammy links. So why disavow? There are a few reasons: If you ever get a manual review of the website by the webspam team and you haven't disavowed you're at risk for getting an unnatural links penalty. You do NOT want that. -There are other algorithms outside of Penguin that look at links. We don't know much about them, but best to be safe rather than sorry. -Even though Google says they are simply not counting spammy links, I wouldn't want to trust their word completely and simply ignore spammy links.