Not trying to revive an old thread, but there seems to be a few old threads about dxm extractions that weren't properly answered so I figured I'd share my method. Feel free to delete post if this is too old or inappropriate. This is a normal base/acid method using vinegar, but is very economical and consistent if done right.

Method:
Dump cough syrup in a flask. Syrups with acetaminophen or guaifenesin are fine since these will be removed. Don't use syrups with doxylamine.

Add base (ammonia or solutions of sodium carbonate or sodium/potassium hydroxide all work fine) until syrup solution becomes cloudy.

Add non-polar solvent (naptha works fine, xylene works fine, limonene works fine). NPS volume should be smaller than syrup volume.

Throw in a stir bar and let it mix for a while (or put in sep funnel/jar and shake). Keep mixing until the syrup layer becomes clear after separation. If it doesn't become clear after mixing for a bit, remove & save the non polar layer and add fresh solvent and mix until syrup layer is clear.

Separate the non polar layer from the syrup and discard the now clear syrup layer. if there are syrup-colored drops in the sep funnel add some water, swirl, and sep again to wash out the syrup dyes.

Take your dxm/nps and put back in flask. Add some distilled white vinegar to the flask and stir it up for a while (or put in sep funnel or jar and shake)

Separate vinegar layer and save. If this has no smell, you can add more vinegar to the nps flask and mix/separate. Once you separate the vinegar out and it still smells at least faintly of vinegar you know you have got all the dxm from the nps.

Combine vinegar pulls and evaporate. I HIGHLY recommend a double-boiler setup (i used 2 little glass bowls on a hotplate with oil in the bottom bowl).
You can use water for the bottom bowl but it will evap too. Cooking oil is good but make sure to leave room at the top because oil expands when heated. Do NOT get impatient at this point or you will burn it and lose the batch.

Once you simmer the vinegar/dxm solution down to a low volume, it will smell very strongly of acetic acid. At this point I usually add more water and simmer it off again (to remove more acid). Once the volume gets low again, turn the heat down looow (until you only see faint vapors coming off it). Once the vinegar/water is gone you will be left with a liquid still, so don't try to boil until you see precipitate. Just simmer on low heat until the vinegar smell is gone. This means all the acid and water is gone and you are left with a thick syrup of dxm acetate.

Depending on how clean your extraction was and how carefully you evaporated the water, the syrup will be anywhere between a clear liquid and something dark like maple syrup. If there are black specks in it or it smells really bad, you burnt it (or you didn't completely sep the syrup from the nps).
This oil sometimes will solidify/crystallize as soon as it dries, and sometimes it will sit as a liquid for a couple days and then spontaneously crystallize. Be patient. It can be used as liquid if needed, but is much easier to dose out once it solidifies. Heating/fans/etc do not seem to speed up the solidification (if the syrup doesn't smell of vinegar then it is already dry, just give it time to set up). The dried product will be a light tan to brownish color depending on cleanliness of extraction and how thick the chunks of solid are. Dissolves in water, but doesn't suck water from the air so it will remain solid/dry even in moderate humidity.

I found this method to be the easiest/cheapest/safest for a few reasons:
1. I like vinegar because the extra acid will evaporate and allows for more accurate dosing (plus I don't like the idea of eating unknown amounts of pure acids even if it is a food-safe weak acid, and lemon juice has lots of unnecessary stuff that will affect the weight/consistency of the product). Some say vinegar leaves lots of impurities, but I use the cheapest distilled white vinegar available and the amount of product is what would be expected if it was pure dxm acetate and dosage is experientally equivalent, so it can't add much and it's safe to eat anyway. I have also tried this procedure with lab grade glacial acetic acid/dH2O and the results were identical.
2. The NPS can be re-used for multiple extractions without needed to be cleaned/distilled between batches. After several batches I have had naptha pick up a very slightly pink color, but it did not affect the extraction.
3. You are going to end up consuming the salt form anyway, so why bother trying to isolate free base and potentially leaving residue from evaporating unclean NPS?

Warnings:
Do not get impatient while evaporating. Burning a batch is never fun. Do not try to consume a burnt batch. If you want to salvage a burnt batch, dissolve it in vinegar and do the extraction all over again (and this time pay attention).
Weigh your doses. It is much easier to overdose with pure dxm than syrup/pills and it is hard to eyeball your dose (the weight difference between powder and solid chunks is dramatic).
Don't use every day for several years. Your brain will fry.

-Treehouse

First off, I have more less damaged my brainb severely fromexxecissive (and by excessive I man excessive; 2 gram dosesmultiple times a week for about a year and a half which stopped around the age of 15-16... Since then there was years of abstinence from it but then more binges starting at 19-20.. Im 25 now and havent touched it in 3 years and though I still get a crazving ( and i man a CRAVING) I will not do it ever again ; I remind myself of the paranoia delusion and cognitive impaorment that follow.

That being said I didnt do anywhere as near of an extreme binge after my first binge when i was 14-16. Absained years and my iq was 143 at 17.

All that said, if your gunna do it your gunna do it.

Extraction:

Dreamer basically said in this thread what ya do. Ammonia is not an option anymore thatnks to meth, the gub tryna control (and fail) things; surfacent (soap) has been added. SO not an option. I have not tried anything but Naoh since the great ammonioa swithceroo.

Baase your syrup. ANywhting with just dxm or dxm and guafensin is fine; the gueaf won't carry over. There is one weird brand that is colorless with just dxm that doesn't work for some reason; its some , lol, "natural" or honey stuff i think.

After base add about 10 percent of your total volume of mix worth of naptha. So say you used 2 8 oz bottles, you should have about 16 oz. So use about 1.6 oz of naptha to pull. One pull ussually worked for me but you could try annother to see what happens.

Dunno about freeze precipitating but we always evaporated. Use hair dryer for quickness. Dont use at the end unles you wanna blow your stuff away. Fb dxm is ussualy pretty fluffy. Add to orange juice and..... the rest is up to you