Will Ferrell, John C. Reilly and Adam McKay are looking to clean up Mother Earth ... by any means necessary.

In a new video for funnyordie.com, the trio goes around teaching people how to be more environmentally friendly -- by using some not-so-friendly tactics. During one eco-lesson, Reilly screams, "Just because I'm an environmentalist doesn't mean I'm a sissy, motherf**ker!"

To see the full, uncensored version, go to funnyordie.com.