I don't remember exactly the amounts but i'm pretty sure you could lose easily 10% of your crystal with even a chilled ammonia wash.
If i were you i'd do this:
1. dissolve your crystal in 100mL room temperature Naptha
2. do three 50mL pulls using white vinegar, combine the vinegar pulls
3. warm up the vinegar and 150mL Naptha
4. do three 50mL pulls using the warm Naptha, combine the naptha pulls
5. freeze precipitate from the Naptha
If done well there will be little to no loss of your crystal and it'll be a lot whiter.
Just keep in mind that the spice will never taste totally smooth, it'll always be at least a little harsh
How are you smoking it?
Another suggestion, say you've got 200mg of crystal, weigh up an equal amount of Mullein.
Put your mullein and crystal in a small glass and pour enough acetone or IPA or denatured alcohol in there to just cover it all. Swirl it around a little and leave it for a few days to evaporate to dryness, smoke this in a bong or a long travel glass pipe
I know i keep pushing this enhanced leaf shit :d but honestly I don't know how anyone can handle the smoke of pure crystal. Like this it is smooth, fragrant, convenient, pleasurable blah blah
Can you put up a pic of your crystal?