Use grep search to strip shortcodes from content – for cleaning up from Visual Composer, etc.
// from https://www.kirstencassidy.com/cleaning-up-formatting-shortcodes/
Export contents of wp_posts.
Open .sql file in BBEdit.
Find-All (with grep turned on) this string:
\[(.*?)\]
Replace with nothing.
Back in phpMyAdmin, DROP wp_posts table. Then import the edited .sql file.