I was told by the guy at the hardware store that if plunging and using a snake don't work, try sulfuric acid. I bought a bottle and followed the instructions, but it didn't seem to work. The instructions say to flush five times when the drain is open, but I don't think it is and I'm afraid of having the acid overflow all over the bathroom. I was told to try pouring in boiling water to try to get it down. What should I do?