Pick up some XTO Energy (XTO), Jim Cramer said on CNBC's "Stop Trading!" segment Thursday."Natural gas is on fire," Cramer said. Calling the company's secondary offering a "special opportunity," Cramer urged investors to get on board. "Every one of its secondaries has been a buy ever since its initial public offering. ... Call your broker and say, 'I want in on the secondary.'" Cramer lauded CEO Bob Simpson, adding that XTO is the best of the natural gas companies, beating solid performers Apache ( APA), Anadarko ( APC) and Devon ( DVN). Cramer offered a less rosy take on Lundin Mining ( LMC), saying, "Someone's gotta put that company out of its misery." Cramer did mention that CEO Karl-Axel Waplan is a "standup guy," for taking conference-call beatings "like a man" every time his company disappoints. As Erin Burnett presented Cramer with several pairs of boxer shorts selected by "Fast Money" trader Guy Adami, Cramer said that anyone relating Liz Claiborne ( LIZ) to the rest of the apparel industry is wrong. The company's shares had tumbled on lowered 2008 guidance.