Jean

Tidy Archives will display your archives in a practical way. It displays links to monthly archives together with direct post links for the current year, while for previous years it only displays a link to the yearly archives.
The format in short:
Month Year 
– list of posts in that month
followed by a list of previous years.
So the idea is to have the archives displayed like this example:
February 2011 
– Post 3 
– Post 2 
– Post 1
January 2011 
– Post 4 
– Post 3 
– Post 2 
– Post 1
2010 
2009 
2008

Tidy Archives

Tidy Archives displays your archives in a more practical way.

Gabrielle Rose

Allows quick and simple deletion of all unused categories and tags. 
In order to maintain your categories structure – unused parent categories will not be deleted if they have a child category still in use. 
For multisite installations unused tags and categories on all sites can be quickly processed at the same time.
<h3>Features</h3>
<ul>
<li>Easily tidy up tags and categories on your site</li>
<li>Maintains your existing category structure</li>
<li>Easy for network admins to manage tags and categories across a wordpress multisite installation. </li>
<li>Translation Ready</li>
</ul>
<h3>Documentation</h3>
<ul>
<li>
Select taxonomies to tidy – categories, tags or both
</li>
<li>
Confirm on next screen
</li>
<li>
For Multisite manage sites individually from each site’s admin or manage all sites together when in NetworkAdmin
</li>
<li>
Users who have permission to ‘manage_categories’ can access this tool ie: Editors and higher
</li>
<li>
Note – Unused Parent Categories will not be deleted if they have a child category still in use.
<ul>
<li>Categories or Tags still linked with content in the trash will not be deleted.</li>
</ul>
</li>
</ul>
<h3>Links</h3>
<ul>
<li><a href="https://github.com/wpplugindev/category-tag-tidy" rel="nofollow ugc">GitHub Repository</a></li>
</ul>

Category Tag Tidy

I recently moved my sites from Multisite to single sites, and some cleanup was required.
This plugin easily cleaned the unused category/tags.
Works pretty good, thanks.

Pretty good

Allows easy deletion of unused categories and tags - maintains existing category structure.

Tidy Archives vs Category Tag Tidy