Cache – Why var/cache Folder Is Not Deleting

Flush and refresh: Refreshing means that it cleans up alle the invalidated cache keys. for example: when you save a widget while the cache is active you get a message that the cache is invalid. In this instance you don't need to flush the cache, just refresh it. Flushing means that it throws all the cache away, it will rebuild everything from scratch.

CSS/Javascript cache: This cache is separate from the default cache. The normal cache will store in a cache-backend. That can be the var/cache/ folder, it can be memcache or redis, etc. The CSS/JS cache is stored in the media/css and media/js folders (you can thus safely delete those folders at will). Flushing browser cache is a good idea, certainly if cache headers are set up. You can also auto-version your css/js files to fix this: https://github.com/fbrnc/Aoe_JsCssTstamp

Flush Cache Storage/Flush Magento Cache: If you flush the magento cache storage it will flush all the cache options that are mentioned in the cache-table. If you flush the cache storage, everything is flushed. By default there is some database caching used by Zend that only get flushed this way.

Deleting contents of /var/cache and /var/sessions: When deleting var/cache everything is flushed except css/js (those are in the media folder). To remove sessions you need to delete the var/sessions folder (you can also store sessions in the database or redis/memcache), but you'll rarely have to. Doing this on a live server may cause problems (carts get lost).

Flushing of the Magento Cache

There are a few options here, namely:

Checking the line items and submitting refresh from the Actions dropdown box
Clicking the Flush Magento Cache button, and
Clicking the Flush Storage Cache button.

and another way:

->SSH users can use the following command to flush Magento caches:

$ find ./var/cache -type f -delete

->FTP users can use the following command to cleanup Magento caches:

mrm -r ./var/cache ; mkdir ./var/cache