Frequently Asked Questions
15. What is that black stuff at the bottom and sides of the toilet? (part 2)

Another reason it keeps coming back is that the mold, or at least some spores, are not just in the bowl, they are in the tank, between the tank and bowl, in the hinges of the seat, and in all the nooks and crannies of the various parts in the tank. You can try squirting some bleach solution up between the tank and bowl. But you need to treat the tank, take a look in there and you'll probably see some mold. Get yourself a bottle of bleach, a cup, and some rubber gloves and a stick. Flush the toilet and before the tank is half full reach down and close the flapper, use the stick if your gloves aren't long enough or you don't want to stick your hand in there for some reason, it's just water. As the tank fills carefully pour in the bleach, save a cup or so of bleach. Just let that sit in there for a while, it is a very strong solution; make sure the area is well ventilated. While the tank is soaking, take that saved bleach and pour it down the overflow tube, that vertical pipe that sticks up above the water surface. That tube leads to the jets or holes all along under the rim there is probably mold in all the channels and jets. Ever once in a while use the cup to pour some of the solution down the tube. After 10, 15 minutes or so flush the toilet and then push the flap back down at the halfway point again and let the tank refill again. Instead of completely flushing and letting that solution just gush on thru, we are trying to keep a stronger solution in contact with the internal connections as long as we can. After another 10 minutes or so go ahead and flush the toilet. You can let that sit in the bowl as long as you can stand it. The chlorine smell will go away after a few flushes. Before you put the lid back on the tank drop in one of those products like tidy bowl, just so long as it is the kind you put in the tank and not just the bowl. Choose a brand that claims to fight molds, it will usually say it has chlorine bleach in it. There are more efficient products available from a local janitorial supply, house and you may find a device which you can fill and refill with your own bleach.