Yeah, I think a history or "older version" beneath (or expanded from) the current one would be a lot easier to work with than duplicates that look near identicle to one another.

I have updated the description. Hope it is clearer now.

The question is about removing a solution. This 'refactor' action does not remove old solution, it just adds a new, refactored one, and leaves the old one published as well.

You can refactor them, which is kind of cumbersome. You need to search look through all your solutions, find the right one, and click on "refactor".

That being said, keep in mind that you gave the CW people an irrevocable licence to publish your content/solution. If the content isn't actually yours to publish, contact them by mail or similar.

You can't.