Summary:Objectives were to measure syringe cleaning strategies used by injection drug users (IDUs) and to assess syringe contact with bleach during cleaning demonstrations. IDUs were interviewed about cleaning activities during their most recent injection episode; they demonstrated these activities on videotape. Coders reviewed the videotapes, categorized activities, and used stop watches to record bleach exposure. Of 161, 146 subjects reported cleaning at last injection, 85 (58%) of 146 used full strength bleach. Of bleach users, 20% had total contact time (duration of bleach inside syringe) of ≥30 s; combining draw (time taken to fill syringe) and contact times, 54% of bleach users had total “flush” times of ≥30 s. Median observed time per bleach flush was 16 s. Median reported cleaning times were twice as long as observed. Recent reports indicate 30 s of exposure to undiluted bleach is necessary to inactivate HIV in the laboratory; here, 80% of IDUs using bleach had contact of <30 s. Judgment of contact time was inaccurate. On average, instructions advocating two bleach flushes may reach 30 s; here, half the subjects had insufficient time with two flushes. The majority showed inadequate techniques, therefore, alternate cleaning strategies should be developed.