If white, glassy shards are what you want, they're not so hard to come by with just a bit of extra effort (or so I am told by my imaginary octopus friend, Senor Tentacles):
1) Using ascorbic acid instead of vinegar for the boils will pull just as much of what you want and less of what you don't.
2) Two or three good defats with xylene and/or naptha prior to basifying will help tremendously - you will see the fats and oils bubble up into the solvent immediately with xylene.
3) A quick carbon wash of your naptha pulls is supposedly very effective in removing any yellow tint (although SWIM has never actually tried this, nor has Senor Tentacles).
4) Freeze precip instead of evap will minimize oxidation.
5) One good re-x afterwards and you can separate most of the remaining oils and oxide (which you can always keep if you want, or throw back into the basified solution, zinc and then pull again).
6) Drying your yield without the aid of a fan should also be helpful in reducing oxidation.
You can always do some final xylene or limonene pulls for the jungle stuff. Nobody says you can't mix and match to find your own personal brand of mojo, but if you're trying to figure out your preference, wouldn't you like to actually have as close to a pure and unadulterated product as possible with which to begin your comparison?
Question for the peanut gallery:
Does anyone zinc up the acidified brew prior to basification, as a part of their usual tek? If so, how much, and is it helpful in any material way?
