Ask HN: Dealing with WordPress wp_options table

The WordPress wp_options table can quickly get filled with a copious number of rows causing page load time to increase and server/db load to increase.

There are several plugins for clearing the entire wp_options table and generally clear all of the posts, pages, comments, etc and return your installation to a vanilla WordPress install; however, I'm looking for a way to remove only the rows in wp_options that are not used anymore.

For example: removing old theme data stored in wp_options, plugin data/configurations, etc.

Does anyone have any tips for even identifying which data can be removed?