Epsom should have a slightly different crystalline structure, as it is a different compound- MgSO4 rather than NaCl. I'm going to try both next time and report back which works better. I'm sure they are both perfectly effective, lol!
Oh man this is funny- I have to share it. So I have this girlfriend, who is awesome. And she has this bong, which is beautiful, and hits like a dream. However, it's not the cleanest pound of glass on the planet, and the ID of the slider had shrunk to a paper clip width due to resin buildup... and the bong is opaque, so we could only judge its contents by odor... which, needless to say, had been questionable for some time! Well, her husband is so attached to the thing that he didn't even want to give it up for one evening to be cleaned, so last week she left a couple joints on the coffee table and snuck out with the bong all bubble wrapped in a box. haha.
It took a full bottle of alcohol, lots of Kosher salt, some soaking, careful heating of the slider under hot tap water, and a LOT of encouragement from various pointy objects to get the gunk out of the slider even enough to stick a q-tip dipped in salt up there, and the bong itself- oh MAN I don't even want to know. I dumped a lot of bong residue down the drain, but did end up saving the alcohol in a glass jar.
The other morning as I was cleaning the kitchen I noticed that all the liquid in the jar had evaporated, leaving behind a thick black jelly. Mmm tar jelly for breakfast? There was EASILY about 1/4 CUP of pure, nasty, gloppy bong goop in there. And that bong is only about a pint total internal volume! Haha.
I totally saved it to show her husband why the ladies had been conspiring against him!