Bulk change font-family and font-size

Hi guys!
Thank you for your awesome job with this plugin, it helped a lot all of us!
I am changing the design on my site and need to bulk change all of my text in posts from one font family and size to another. TinyMCE added <span style=”font-family: georgia, palatino, serif; font-size: 12pt;”> everywhere in <p> tags. I need to remove this tags everywhere or change them all at once. Is there any solution or trick maybe?

https://wordpress.org/plugins/tinymce-advanced/