Attachment Page Errors – WordPress Seo by Yoast

I’ve written a few posts on the wordpress seo plugin but would like to know about attachment pages

I’m getting 404 errors on many like these. Is it better to non index them somehow?

https://wpsites.net/?attachment_id=2896
404 (Not found) 7 pages Nov 10, 2011
https://wpsites.net/?attachment_id=2882
404 (Not found) 7 pages Nov 10, 2011
https://wpsites.net/?attachment_id=2930
404 (Not found) 7 pages Nov 10, 2011
https://wpsites.net/?attachment_id=2909
404 (Not found) 7 pages Nov 10, 2011
https://wpsites.net/?attachment_id=2883
404 (Not found) 7 pages Nov 10, 2011
https://wpsites.net/?attachment_id=2400

I would like to update my posts about the WordPress Seo plugin with the solution to these errors. Thanks