Increasing the amount collected for recycling is useful only if the material can actually be processed and marketed. Contamination occurs when trash, food, plastic bags, or other unacceptable material is mixed into a recycling stream, potentially increasing processing costs or causing otherwise recyclable material to be rejected. Oakland County's Materials Management Plan work program includes best-practice analysis, enforcement planning, and an education, outreach, and marketing action plan, allowing the county to consider both resident behavior and system design. Collecting more isn't the same thing as recycling more. The useful question is which intervention gets cleaner material without making recycling so annoying that people stop participating.