So when you finally take the jar out of the freezer,
(having pre-drained the solvent off and put the jar back
inside inside the freezer upside down for 5 mins or so....

So then you take it out and try to warm it to room temperature
using a fan, and water condensation in the air - on the sides of the jar
turn your crystals to mush ...? Sound familiar ?

So you get a 50 Litre plastic tub from big hardware store.
You get old computer fan, and use an old phone charger / adapter
for a power supply.

Fill the bottom inch or so of the tub with damp rid crystals (calcium carbonate?) - available at same hardware store.
Stick a plate / similar inside, with the fan.

Take your jar straight from super-cold freezer - onto the plate in the
0% humidity box. Have the fan running - jar and xtals should warm to room temp, without mushy nightmares...

Seems to be work better than just open air blown over cold crystals.

id leave it upside down for a lot longer than 5 minutes.
also putting it in the fridge upside down instead of the freezer works great.
leaving it in the fridge until the condensation clears might help you out too.