I know this is an old thread, but people will find this thread useful in the time to come.
The problem here is you really need anhydrous 100% pure acetone. if even 1 drop of water is in your acetone your using this let's say on chilie, that one drop can carry up to 1/4 gram of your dinner away with it. Imagine what a few drops could do?
It's easy to get 100% acetone, most any 5 dollar nail polish removers will say right on the label, 100% pure acetone, but in chemistry one should never believe the label, especially on a 5 dollar product, stuff happens, so prove its pure and keep it pure by getting some 98cent epsom salt, the only thing here is it has to NOT be iodized. Try kosher salt or canning salt maybe, read the label.
Bake epsom salts, slowly increasing the temperature and stirring to prevent clumping, to just over 200? C (right about 400? F); I would leave it there for 45 minutes or so. Do not add the hot result to the acetone yet. personally I baked it on foil, allowing me to fold it in the foil, let it cool for a minute or two, and then immediately put it in a ziploc bag (which I put in another and then another) to prevent it pulling moisture from the air and rehydrating.
Once it?s around room temperature, 1/4 way fill a mason/canning jar (with a metal lid! acetone eats plastic and rubber) with your anhydrous magnesium sulfate (dehydrated epsom salts). Add acetone to fill the rest of the way. Put the lid on tightly, and put it all in the freezer ? you won?t freeze the acetone, don?t worry.
This is to a) keep your acetone from trying to evaporate and pressurizing your jar, but much more importantly b) to keep the solubility of the salts in your acetone as low as possible. Do you want salt in your dope? No, right? Keep it cold.
When the time comes, put your dope on a plate or a coffee filter (I use a plate) and use an eye dropper or pipette or syringe to draw acetone from the TOP of your jar and dribble it on your dope. Your dope won't dissolve and will stay in the coffee filter/plate; gak that is soluble in acetone, which quite a bit of it is, will dissolve and go through the filter or it'll go into the air with the acetone as it evaporates.
If your like me, leave the acetone in the freezer and top off as needed, you'll be using the anhydrous acetone often.
If you make your own chile and something goes afoul and the end product has an off taste, this may fix that too.