I have recently checked my backlinks, and found some real shitty pbn links, that I built long ago with some seo-guy. Backlinks now like RD5 - RD10, and the sites are being pbns for 4 years, having a ton of outbound links to "whoknowswhere". I dont have manual penalty, just noticed smaller-bigger drops in serp according to the newest updates. The anchors on theese sites are quite aggressive exact-match, and partial-match anchors. I am ranking almost fine for those keywords, but cant break into top 3, no matter how many powerful pbn links I build (brand,url), so decided to take action on the weakest ones. Is the exact match anchor on a really weak pbn is passing ranking power for my site so just leave it there, or I can delete that because it has no use but messing with my anchor text ratio? Some of you will say, "leave it there, and build more powerful backlink", but note that I think somethings messed up here because the competitors outranking me with real weak, inner sites. So I just want to do it the best way. And dont want to waste 10 of my pbns for some inner site to just dilute bad pbns. They might have some better use.