Sorry, as far as I know, Firefox doesn't have Trash. Is this on a particular email website where you can't empty the Trash?

It might help to post a screenshot of the error message. This article has tips on capturing screenshots: How do I create a screenshot of my problem? Please cut out or blur any sensitive information before attaching the image file to your reply.

I am cleaning up - to update this computer. Currently in the App Folder is Firefox 46.0.1. It had trash dating back to 2012. When it would not empty trash and gave an error message - I worked a little at a time finally deleting all trash except (2) Firefox 30.0 Apps that were in the Mac trash. These are the cause of the error code when trying to clear the trash on the Mac cmptr. How can I get rid of these files from this Mac?

Oh, the Mac trash folder. As a Windows person, I have to confess complete ignorance about that. Hopefully a Mac person can advise here, but if you don't get a quick response, try Apple's forums.

Try:

• https://support.apple.com/en-us/HT201583

• http://www.thexlab.com/faqs/trash.html
• http://www.macupdate.com/app/mac/8214/trash-it