Drain opener is not always the best solution to fixing your slow drains. Most drain openers are acid based. As with any acid it can react to different parts of your drain and cause some big problems. If you have a slow sink you should first try removing the p-trap under the sink. This p-trap has a couple jobs. The first is to prevent odors from coming out of your sink. The other is to collect things like that ring you may have dropped down the sink. This p-trap also collects things like hair which causes your drains to slow up. Be sure never to pour drain opener down your toilet. If your drain opener is acid based mixing a little bit of acid into that large amount of water causes a chemical reaction which causes extreme heat. This heat may cause the porcelain to crack. Not all drain openers are the same. Some of them may be safer than others. Please read all of the instructions on your drain opener before using it or consult your local plumber. If you have any questions please e-mail.