Messages customization statistics

I have now deleted 370+ translations on Wikimedia Commons where the message was identical (or less useful) than the default translation. In nearly all of these cases, the translation message was created before 2008. We should create a list of all languages, and check them off as we have reviewed all of the custom messages on Commons and/or <lang>.Wikipedia.

• I have checked that there are no messages identical to the default nor any custom versions in the Welsh version of Wikimedia Commons. Is this because it is not the site language?
• Don't you have to be an admin on a site to delete messages there?