I recently spent a week or so trying to unclog a seriously blocked kitchen sink drain. I tried various things, including One Shot Instant Drain Cleaner (a hardware-store 91% sulphuric acid drain cleaner).
My attempts all failed and eventually a plumber managed to solve the problem in about five minutes' flat with a glorified Henry Hoover...
Alas, I hadn't noticed at the time that I'd spilled a small amount of the cleaner on my sideboard. It's now dried into a thin layer of a cement-like material. Scraping it off with a screwdriver seems like it might eventually be successful, though after quite some time and I'm concerned about damaging the sideboard.
Is there a compound that I can use to just dissolve the dried drain cleaner, or at least convert it into some form that I can then clean up? Boiling water on its own doesn't seem to do anything at all.
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