Instruct: Classify a review as either positive or negative.
Query: Tried several different brands, this is the least effective

These balls seem to be effective for one medium load of non towel/cotton laundry. Then there seemed to be a buildup of static in the balls and they became ineffective on the second load. After leaving them for a few days I tried them again and they again worked for one medium sized load of laundry. On the third and final time I tried, the towels were completely filled with static.It seems to take a few days for the built up static charge to dissipate and to be truly effective you would need several sets of these balls, which kind of defeats the purpose of the idea in my opinion.I have yet to find an effective version of this idea but I will keep looking, just not at these.