Why RV Black Tanks Clog Easily If your RV black tank is plugged, we recommend using Unique Clear-It and follow the instructions on the bottle. We use this product on our customer’s RV tank clogs. Unique Clear-It: https://amzn.to/3YWRgjj You can find the products we use repair and maintain RVs in our Amazon Storefront (products are organized by ‘Idea Lists’): https://www.amazon.com/shop/radarroadwarriors | Mobile RV Tech Services