Rather than provide development assistance indefinitely, foreign aid donors increasingly seek to help communities sustainably provide local public goods themselves. We examine various strategies for sustainably fighting intestinal worms through voluntary local mobilization. Intestinal worms affect one in four people worldwide, but can be controlled by taking medicine twice annually. Since much of the resulting treatment benefit comes through reduced disease transmission, standard public finance analysis provides a rationale for subsidized treatment. Randomized evaluations suggest several efforts to replace subsidies with sustainable worm control measures were ineffective. A drug cost recovery program reduced take-up by 80%. A mobilization intervention designed to boost drug take up failed. Health education did not affect behavior. People were less likely to take drugs if randomly exposed to more information through their social network. In this context, using external interventions to promote sustainable voluntary provision of local public goods (like worm control) appears unrealistic.