Do not microwave!!! Put the bag in some hot water. Or look in marketplace for a used bottle warmer. They can be pretty cheap
@Emma okay thank you!
@Karol perfect thank you!!
I've not thawed frozen but I boil water in a kettle and then place the bottle in the thermos. Ours is 6 minutes for thermos and 8 minutes for our 500ml jug as ours likes it a tad warmer then body temperature. Frozen I would put in the fridge to defrost but there is advise online how to do it safely
Do not put them in the microwave!!! We put ours in hot water and wait until there’s no ice left, my baby girl doesn’t mind that it’s not ‘warm’.