Negative Crawling - Harmful Wrong Things
Crawling is the major process on the web and negative crawling from an SEO point of view is bad. Because it has a bad effect on your ranking. Suppose you have 404 pages on your website that are noticed by webmasters.
Then the webmaster thinks about the overall quality of the website. According to me, you don't need to remove outdated pages. You can update them. This is a good alternative.
If you have a web page that you want to remove just for URL that does not have value in search then you do permanent redirect with the new version of the keyword. That will become your new destination.
Moreover, it is not a good idea if you redirect your 404 pages to a new location. Just leave Google automatically remove the 404 web pages. But you can tell Google to immediate removal about your Zomby pages.
Moreover, read Zomby Vs 404 Pages.
You can remove URL under legacy tools and reports within the search console. Just go to removal.
Negative crawling with duplicate pages.
Never create a duplicate URL, Title, and WEB Page content.
It is harmful from an SEO point of view and also Google search console notice this.
Keep clean your webmaster account from warnings and errors as much as you can.
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