deeper - 6:07 pm on Jun 30, 2013 (gmt 0)
Yes, this is the video I meant....
You say "when you remove links that have been discounted, you may not have enough remaining links to bring up your rankings to where they once were".
But this is only true when discounted links still have any value, right? You are talking from links being discounted but still have a little bit of value and therefore a great number of them help ranking.
This means, links with a value of "0", discounted completely can be disavowed without any risk.
Backlinks from DMOZ clones, weak directories... do they have a value of 0 or 0,2 in a scale up to 10? Noone knows.
Probably "Link Research Tools", a set of professional tools for backlink analysis.