Hello. I have a toto toilet with some mineral deposits in the siphon jet, and I am thinking it could use some descaling. I have read on the forum about the virtues of using muriatic acid for this, but I am afraid of possible damage to my drain piping (copper and cast iron). I tried using CLR in the bowl for several minutes, but it didn't do too much. Can someone confirm that a bit of muriatic acid won't immediately dissolve my drain pipes? I don't really feel like taking the toilet outside because it's not too much of a problem at the moment. Maybe I should use a weaker acid like CLR or vinegar for longer (hours instead of minutes)?