SharePoint 2010 uncustomize a page layout

 To uncustomize a page layout or master page,

1) Using C#: http://dirkvandenberghe.com/2009/03/24/how-to-ghost-back-page-layouts.html

http://jamestsai.net/Blog/post/SPFileCustomizedPageStatus-amp3b-SPFileRevertContentStream-The-way-to-check-SPFile-GhostUn-Ghost-status-and-Revert-to-site-definition-via-code.aspx

2) Using powershell script: http://admin-sharepoint.blogspot.co.uk/2013/05/unghosting-customized-page-layouts-with.html

3) Using SharePoint Designer: http://mosshowto.blogspot.co.uk/2008/10/re-ghost-master-pages-sharepoint.html

4) Using stsadm: http://blog.ithinksharepoint.com/2011/05/10/issue-with-updating-sharepoint-publishing-page-layouts-and-ghosting/

5) Using site settings, though this works for a normal site page, I am not sure if will works for a page layout or a master page: http://rolandoldengarm.wordpress.com/2012/01/23/page-layouts-in-master-page-gallery-not-updated-after-a-deployment/  

6) Free utility: http://www.codeproject.com/Articles/514279/Ghostplusun-ghostedplusSharePointplus2010plusfiles

To disable customization
http://blogs.msdn.com/b/steve_fox/archive/2010/03/08/ghosting-unghosting-in-sharepoint-2010.aspx

other references:
https://www.google.co.uk/search?q=sharepoint+2010+customize+page+layout&oq=sharepoint+2010+uncustomize+p&aqs=chrome.1.69i57j0l5.20326j0j8&sourceid=chrome&espv=210&es_sm=93&ie=UTF-8#es_sm=93&espv=210&q=sharepoint+2010+unghost+page+layout&start=10