I happen to be a great salvager, but that can be its own downfall. Sometimes, while editing a document, I will realize that what I want to add or change doesn't work. I'll spend minutes looking and toying and changing and rechanging sentences, both in order and construction, and I will grudgingly accept that the sentences can't be salvaged.
At that point, I have to accept that and start to build a whole new sentence to make the passage work right. But the real lesson here is that it's not easy to let go. Even when it's not your writing, it can feel strange cutting away others' words. But if a passage is best served by not salvaging what's there, then eliminate that which is unsalvageable for the sake of making the best product.