Society conference, which was also explaining the potential use gunshot residue, the presenter stated that many chemical cleaners, specifically those designed remove motor oil or freight dust, can give a false positive for the Modified Griess Test[20]. Previous studies have shown that some materials produce a positive reaction in the Modified Griess Test. A disinfectant spray containing nitrites END BAC II, manufactured by the Johnson Wax Company reacted positively with the Modified Griess Test 121]. The was tested by spraying at various distances and angles product a test cloth, and although positive reactions were observed, none of them were consistent with the pattern that would be created from gunpowder residues[21]. A positive Modified Griess Test reaction was observed on a shirt which contained small amount of marijuana in the pocket, but again the pattem was not consistent with that of gunpowder residues[22]. Another study examined three cured meat samples, nine cleaning agents, two nitrate containing substances, marijuana and one herbicide and found that none of the substances reacted with the Modified Griess Test in a manner that would generally be confused with gunpowder residues[23]