The practice of dipping marijuana cigarettes in embalming fluid has been around for years. But some experts say the potent combination is becoming more of a problem in New Jersey, where it figured in a recent shootout that left one user dead, one wounded and one other person injured. Known on the street by numerous nicknames including “illy,” “leek,” “crazy Eddie,” “wet,” “amp” and “purple rain,” the formaldehyde-laced marijuana, sometimes with PCP added as well, has been around for at least 20 and possibly 30 years, said Doug Collier, a spokesman for the U.S. Drug Enforcement Administration in Newark.