gulp. How to remove unused selectors from SCSS in final CSS?

Question

css

I am using the UIkit framework . In my SCSS file I include the SCSS file from the framework. The SCSS framework is very large. I definitely don't use all the selectors from it. But they still compile to my final CSS file...
Question :

• than (what plugin for Gulp?) and how?! should I filter out the used selectors from the SCSS framework and leave them in my final CSS file, and "remove" (not compile) those that I don't use from (into) the final CSS file?
  

Thanks in advance for your replies !