Keep an eye on coffee filters
Something to remember if you come upon someone carrying coffee filters: I recently collected what I thought to be several poorly rolled joints only to find them empty. They were coffee filters. The perp explained that he bought them from his meth supplier for less than he would pay for meth. The filters had been used during the manufacturing process and were saturated with meth, which lab tests confirmed. He runs water through the filters and injections the remains. His girlfriend simply smokes the filters.