I always assumed bestine brand rubber cement remover was the best solvent source.. as it only contains heptane and not a mixture of solvents.. if you can find Bestine and it is still the best source for heptane SWIM would use that if available.. I see there are websites which you can buy it from if you can't find at a local art supply.

yes Limonene is safer, but I have heard that due to its increased solubility in Limonene that the technique of freeze precipitation isn't as viable, also that the end result will not be as crystalline as much as a goo as it dries differently.. I've heard the limonene residue can leave a nice after taste and possible increased effect due to insulating the delicate active compounds from heat during vaporization.

According to 2016 Material Safety Data Sheets , both Klean Strip and Jasco are made By W.M. Barr of Memphis . Both list hydrotreated light naphtha as the only hazardous ingredient at 95-100 % concentration. I cannot find more recent MSDS.

I use it as a stained glass artist to clean leads with too much putty adhering to surface. It smells pretty bad in that context and is part of why I have been reluctant to try extraction since it is the main method described by Erowid. Erowid is where I first looked for such info. It sounds like it evaporates clean, though.

The MSDS on Bestine shows n-heptane as only dangerous chemical and the only chemical listed..

There are 2 non-petroleum sources of heptane: petroleum tree from Philippines and Jeffrey Pine. Could not find where one can currently get heptane distilled from these sources.

Jonabark, I remember seeing that 95%-100% on the MSDS as well. I remember thinking, "Oh God. That could be 5% anything. Water. Oil. Polystyrene..."

Yes ficus-a it leaves room for concern. And there is also the question of how reliable MSDS is . But assuming they do a good job the 5% seems more likely to be an imperfect concentration, a logical by-product of making naphtha( since it is sometimes 100%) than a toxic additive or separate chemical.

Not trying to advocate any position here. Just trying to bring in available information that might be helpful.

I wonder though, since naphtha seems a common chemical for this kind of extraction, if a college lab, for example would use hardware naphtha or something from a chemical lab supplier with 100 percent naphtha. or if there are better, safer, current practices? Anyone?

100% heptane would be safer and create a purer product than naphtha which is a mixture of hydrocarbons itself.. Heptane pulls NN-DMT more selectively and makes a purer product than naphtha, also having a consistent boiling point as it only contains the one chemical.. hency why I suggested using it earlier in this thread..

Naphtha; Low boiling point naphtha 8030-30-6 100%
N-hexane 110-54-3 25 - 35%
Xylene 1330-20-7 25 - 35%
Toluene 108-88-3 15 - 20%
Cyclohexane 110-82-7 15 - 20%
Pentane 109-66-0 15 - 20%
Heptane [and isomers] 142-82-5 12.5 - 15%
Ethylbenzene 100-41-4 5 - 7%
Benzene 71-43-2 3 - 5%
1,2,4-Trimethylbenzene 95-63-6 2 - 3%
Sulfur 7704-34-9 0 - 1.5%

Naphtha can contain all these and more.. which makes it the easiest obtainable solvent but not the safest or best quality solvent to use.. the large range of boiling points means that some elements will boil off long before others.. ensuring you have removed all the different chemicals through air drying is more difficult when using a mixture of hydrocarbons like this..

I just bought some Jasco at Lowes two weeks ago and it evaporated cleanly. Just my 2 cents.