^ How would you go about washing/purifying the meth that has accumulated to a substance thats clean enough where you would happily bang it?
There are two basic steps: acid-base extraction and recrystallization. In acid-base extraction, the product (usually a basic alkaloid-like thing, e.g. DMT) is dissolved in acidic water and filtered to remove residue. Then a base is added, and the product generally comes out of solution, forming a cloudy mess; then a non-polar solvent is added (usually stirred a little too), which dissolves the product and forms a separate layer (phase); these are separated and the product is removed from the NP solvent-phase by evaporation or acidification with e.g. tartaric acid. The principle is that impurities which do not have the typical acid-base behavior of methamphetamine will be lost during the process: either they remain in the water phase after basifying, or they remain in the nonpolar phase after acidifying, or they were filtered from the acidic water before beginning.
In recrystallization, one prepares as concentrated of a solution as one can muster of the substance in a hot solvent or solvent mixture, such as ethanol/water. The idea is to use as little solvent per gram of substance as possible; things usually dissolve easier when they're warm. Then the solution is cooled, and the solubility of the product in the solvent decreases, causing it to crystallize. This is most effective if the crystallization is slow, so in general one performs the rextal'n in a very clean glass without disturbing it. The principle is that the desired compound is present in large amounts, and so will exceed solubility limits (supersaturation) when the solution is cooled, but impurities are present in small amounts, and so will not become supersaturated when the solution is cooled -- they will remain in the solvent, leaving behind a cleaner product. Since this depends on the assumption that there is only a small amount of impurity, rextal'n is generally effective only for things which are already reasonably pure. Sometimes the recrystallization is repeated multiple times.
Recrystallization is pretty easy, but it depends fundamentally on already having something mostly pure. Please keep this in mind.
One could imagine purifying crude meth -- or even desomorphine -- by these processes, but I wouldn't be happy to bang it; I don't think I'd ever want to inject methamphetamine at all. I hope this rather detailed explanation of purification does not violate any rules.
If you have no experience with this sort of thing, I would
strongly recommend against attempting any purification procedure with an eye to injecting the result. It's better to find someone who sells a clean product, even if you have to pay more for it, or you'll end up paying a whole lot more in the long run.
