22.7GB for storing "org.mozilla.pluginContainer" even after deleting Mozilla Firefox I deleted Mozilla Firefox and I checked my file storage and saw that within my caches folder I have a folder called org.mozilla.pluginContainer which contains a fsDataCache folder which is taking 22.7GB of space. 

Can I simply empty that folder as I am not sure whether that folder will have any effect on other apps within my laptop. Is it safe to remove that folder completely?
You can safely delete the contents of the fsCachedData folder.

If you're still worried, don't delete the data immediately but copy it to a different folder. You can then delete it after a few days if you haven't experienced any problems.