Sentence:  With his nostrils ravaged, Crosby turned to drinking Cocaine mixed in glasses of wine, then took to smoking it by the novel technique of <WSD>freebasing</WSD>, where the drug is distilled down to its purest form through a process of filtration using ammonia and ether. 
Meaning of the word marked with <WSD> tags:  To use a purified drug, especially cocaine, by heating it and inhaling the fumes produced.