I agree with aesthyrian. ISO and salt wont hurt your pipe But if you do keep it clean, you wont need the salt, ISO alone will work and the taste of your preferred blend will be so much better if you just give it an iso shake once a week. If you think about it most of the cleansers grunge off, 4:20, ect ect have a salt like substance in them. im not sure about grunge off i haven't used it in years. The new 1 minute all natural 4:20 cleaner is amazing if you want to spend a few bucks, and i reuse it over and over until its so gross i have to get rid of it. I clean my pipes once a week, but when i first used the 1 min 420 it was on this disgusting combustion tube, that was caked with resin. And it was gleaming within a minute of shaking. ANSWER - no salt wont hurt, unless you pour it into any open wounds and your eyes. ;-)