The cannabis industry's most widely practiced post-harvest decontamination method — washing freshly harvested flower in a solution of lemon juice, baking soda, and hydrogen peroxide — is chemically self-defeating, biologically incomplete, and commercially destructive. This white paper presents a two-part scientific argument. The first part demonstrates that the DIY wash fails the product: citric acid and sodium bicarbonate undergo immediate acid-base neutralization when combined, eliminating both their antimicrobial acidity and fungistatic alkalinity before contacting a single pathogen. The resulting solution provides less than a 3-log pathogen reduction — among the weakest of any tested household disinfectant. Hydrogen peroxide presents a concentration dilemma: lower concentrations may provide insufficient oxidative activity for meaningful pathogen reduction, while progressively higher concentrations increase the risk of oxidative damage to terpene chemistry and other phytochemicals responsible for product quality. The second part demonstrates that the DIY wash fails the consumer: mycotoxins produced by Aspergillus and Fusarium species are chemically stable compounds that survive washing, survive combustion in modified forms, and enter the lungs directly when cannabis is smoked — even when the active mold colony has been killed and the product has passed total yeast and mold compliance testing. A 2025 Arizona State University study found 16% mycotoxin prevalence in cannabis samples, with fusarenon-X levels reaching 500 to 1,700 ppb. The paper concludes that prevention through standardized, calibrated, professionally formulated decontamination is the only intervention that addresses both failures simultaneously.