A good article about a Canadian fund manager and commodities.
There is a mention of a clean coal stock called KFx Inc (KFX). I just looked into it, it looks very speculative.
While one director just made a purchase, the company makes no money, and the short interest is huge, which is generally an extremely negative sign. To see short interest, look at the linked page under "Share Statistics" at "Share % of Float"; currently, nearly a third of the stock available is sold short.
A news article is available from earlier this year on KFx.