You can also hand express to get rid of the engorgement - many babies don't actually like attaching to engorged breasts, because they are harder to suck.
Hand expressing directions here: Parenting and Child Health - Health Topics - Breastfeeding - expressing and storing breastmilk
And if you don't want to keep the milk the easiest thing is usually to just squirt it down the sink or the bath or into a big towel.