I have tons of 404 crawl errors(my old url's).. I deleted them via Google Webmaster tools > remove url tool..
example: www.mysite.com/page1.html
But there are some external source sites which link my old urls on their content pages (ex: www.anothersite.com).. And because of they have my old urls on their pages, my url removal always fails..
What can i do now? i cannot delete these links; i don't know who is these websites owners.. And there are tons of external URLs like this; i cannot delete one by one via pressing button again and again.
Can robots.txt be enough? or what can i do more?