Hi all, I have a site with good visibility in google with 50 pages indexed, can I clean it from google index with in a day, as I want to change my business theme very sooner.
Not really. You can request them to remove you from the index. Make a direct support request here:- _http://www.google.com/support/ and after a few email chains, if you are finally getting a mail from , Its removed permanently.
Better not to use nofollow tag. You can have some problems with bringing it back to the index (for sure it will not be a quick way). So better just create a new site, and wait for Google update it cache and index. Or just get new domain for your new site.
Change your theme, Google will update the index of your pages, but listen, if you are changing to different URLs, use 301 redirects from old pages to relevant new pages. That will really help Google index your site the same way it did with the previous layout. IT
If you want to remove your whole site just go to [SIZE=-1]www.google.com/webmasters choose [/SIZE]sitemaps then url removal and choose the option to remove your entire site.
It is really different for everyone, so no on can give you a precise answer. As said before, it can be some days, or weeks. But anyway - why do you bother with that? Change your site, and just wait. Not much more you can do (you can change and resubmit your sitemap in Google's Webmasters tools, for example, or use 301, as written above).