They don't need to be removed at all, if you live in zone 7 or below. They will just bloom in the same place next year, for several years. However, if you want to move them, wait for the foliage to totally turn yellow and dry out. You shouldn't ever cut back the foliage while it is still green, it will kill the bulb. Then you can dig them up and keep them somewhere where they will experience a winter chill, the fridge is good if you don't want to replant them outside, or if you live in an area where you don't have at least a couple of months of cold weather.