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Canonical reference links are the preferred technique for this. If you do nothing, very likely the search engines will decide for you which variations of your pages to index, and the selection may not be ideal. If an index page can be filtered many different ways, the unfiltered version should be referenced as the canonical on each, and a self-referencing canonical link should also be specified on the unfiltered version. You don't really yet want to disallow the crawling of the refinement paths, because without canonicals implemented, you might very well do more harm than good, finding important pages getting de-indexed. If at some point in the future you find that all the URLs from the refinement paths have been disappeared from the index, and your desired pages are all indexed properly, then at that future date you might want to disallow crawling of the refinement paths (in your robots.txt file). But, not yet, IMO.

Thank you so much! You've understood the situation correctly and this is the most helpful answer I'd wish for Thanks again.