How to generate new CSS

You can use the Regenerate CSS tool. But it almost sounds like you are manually removing code and if so, then this may not work the way you want. In any case, hope this helps.

When I delete sites made with Elementor, the CSS for theses site in particular still remain and aren’t used sitewide.

For better clarity, what do you mean by “delete sites made with Elementor”?

-Are you using WordPress as a Multi-Site installation using sub-domains or sub-folders?

Can you inspect this css and identify it’s path (where the css exists, what file and where), might help w/ what needs deletion. If you’ve found an Elementor bug please report it in the official GitHub for Elementor page (https://github.com/elementor/elementor/issues). ty.

-Or do you mean “pages” instead of sites? i.e. when you delete pages built in Elementor, css specific to that page still exists elsewhere on the site?

This can happen. Sometimes the css remains in browser cache. Especially Chrome, if signed in w/ an Google account, some caching is applied at the account level where even clearing cache from dev tools or using incognito doesn’t clear right away but after a short delay Typically 10-15 min).

Using a different browser can help you “cache bust” using very simple logic…if the new browser doesn’t display the old browser’s behavior, it’s most likely browser cache related. But if the new browser shows the same as the old, it’s either that it didn’t get deleted properly or it could be some other caching mechanism like a WordPress plugin or a service like Cloudflare.

-If it’s an actual “site” being deleted, isn’t everything in it’s root removed thus no css could remain?

Again, inspect this css and try to find out it’s path using the browser inspector. It has to come from somewhere and knowing this is crucial to determining why it still remains.

How to make Elementor generate a whole new CSS-file?

The only way I know of is to use the regenerate css tool like @cavalierlife mentioned above.

Ah thanks for the clarification. When you delete pages built with Elementor they do not initially delete from the site but rather are marked as trash and must be removed from trash as well. In this scenario the css files will still exist and is normal, especially in case of restoring the page.

I would expect when removed from the trash that Elementor also remove any associated css files to that specific post ID but if not and you can see the files (I think /wp-content/uploads/elementor/) then we likely need to open a ticket with Elementor to find out why they are not being deleted.

I haven’t tested this personally but another thought comes to mind, if you were to edit the pages w/ Elementor prior to deleting them and remove everything from the page and then save over it as a blank page and then delete and empty it from the trash. Do you still see the css?

I would expect this action should overwrite the css file and at least remove the declarations in it.