All sounds good...
I think freezing is best...The 'powdery dots' you see are crystal growing (see pic of closeup)
Scrape those up (with whatever gunk/oil is there with it) and when you have enough you can Re-crystalize it to refine it further...
Around 5 or 6 pulls will exhaust 50g of bark.
Heat can help draw more up but it may get a bit yellow...
cyb attached the following image(s):
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Snow Globes (3).JPG
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