Moreover, a strictly price-based comparison between clean and dirty energy ignores many of the other non-market barriers that must be solved for clean energy to adopted on a meaningful scale, such as regulatory and infrastructure hurdles, issues with intermittency, technology risk, and other barriers.

FORBES: The Carbon Tax, Then and Now

However, if your mother-in-law is otherwise clean (washes her hands regularly, spot-cleans parts of her body that are dirty on a daily basis, and wears clean clothes for example) and is fully responsible for herself in other ways, this issue may not be a problem for her.

CNN: Is bathing just once a week healthy?

What does a dirty-fuel player like Consol want with a clean-burning fuel like natural gas?

FORBES: With Gas Deal, Consol Strives To Turn Coal Green

Zalambessa looks like a very clean suburban town - even from the destroyed town one can not see a dirty house.

BBC: De-mining in the Horn

More fascinating, less dirty - Dyson now engineers motors in a room so clean no pollutants, pollen or dirt can damage the finely tuned technology being made by the highly calibrated production line.

BBC: Technology

When the Rabbi reminds his would-be student that the man with the clean face will objectively see a dirty face and therefore wash, he is reminding the young man of the importance of modern objective thinking.

FORBES: The Rabbi's Four Leadership Lessons, Part 3

With the R-22 price spike HDSN can now pay contractors for the dirty gas thereby getting supply to clean up and decreasing the amount of gas that gets into the atmosphere.

FORBES: Money Managers Pick Six Green Stocks for 2013