"Not made to be refillable - but can be!"
This made a difference to damp/ fogging up of our (small car) windows. I didn’t want to discard it, so I removed the spent crystals, refilled with dehumidified crystals and secured these by fixing a piece of thin cloth, cut to size, over the bottom bit with elastic. The elastic from bunches of spring onions does the trick, and it continues to work nicely. One small bugbear: this moisture trap falls over quite easily and can then leak liquid, so placement is important - I admit I fixed it down with blu-tac…