I have same experience one month ago. Just go to Homedepot and they have a bottle of liquid for this situation and you also can find "Chuai(3) Zi(1) " there. I bought both.
-hotpot(麻辣烫);
2002-2-14{95}(#368706@0)
And I solved with "Chuai(3) Zi(1)" , then I use that liquid for clearing the potential stuff.
yes, i bot "Drain Opener" and put some into the drain, but because there's water in the drain, it didn't work.
-banker(见面熟);
2002-2-14(#368712@0)