I want to temporarily seal a toilet drain so that I can fill and soak the bowl with a solution of hydrochloric acid to remove mineral scale. The seal has to be water-tight so that the solution can sit for several hours.

I have tried jamming plastic bags and water balloons into the drain but they don't form water-tight seals.

(I found two products, designed for this purpose, consisting of inflatable rubber bladders, but they are only available in the U.K.)

  • Quite often design for, can be a name change only. Those products not much more inflatable bladders.
    – crip659
    Apr 21, 2022 at 18:28

1 Answer 1


I came up with the following hack: I wrapped an air wedge in strips of rubber from a bicycle inner tube like so: Air wedge wrapped in rubber

Jamming and inflating it in the toilet drain as in the following photo, the bowl lost less then a cm of water height over the course of three hours. Air wedge + rubber toilet plug

  • Were you able to remove mineral scale using this hack? Have you found a better way to block the drain?
    – tunafish24
    Sep 12, 2023 at 9:22
  • @tunafish24 No to both. I've found that scrubbing with drywall sanding screen is the best way to remove scale from glazed fixtures like toilets.
    – feetwet
    Sep 12, 2023 at 13:27
  • Which ingredient & how much did you use when you filled it up water?
    – tunafish24
    Sep 12, 2023 at 14:52
  • @tunafish24 I tried adding muriatic acid to the water – quite a bit. I don't know why it didn't work.
    – feetwet
    Sep 12, 2023 at 16:08

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