Consider for a second your website gets a lot of spammy backlinks. I know this is not the kind of things in SEO we want to think about but it happens. And the best way you’ve got to deal with it is first to project yourself onto the situation.
So, your website gets spammy backlinks, a lot but all, without exception point to an older version of it.
An older version which is now a pure and logical 404. The question is what should you do to fix spammy backlinks on old domain. They all point to an older version of the site, which is now 404’d.
There are 3 possibilities
Regardless the situation, all is not lost, on the contrary :
- If you find the backlinks valuable then you could redirect those pages to the home page or a similar page on your new website.
- If the backlinks are dangerously spammy (links contain malware, viruses, and dangerous content) then disavow them.
- If they are just random websites then it is fine to just leave them.