Dead maggots are a superb bait when fished in big bunches for carp in the margins. I also find they have the knack of singling out the bigger fish as they don’t wriggle about like live maggots, so they tend to attract fewer little nuisance species.
They’re also very good on the feeder as, unlike live maggots, they don’t cause your hooklength to spin up and twist when winding in.
I always freeze maggots to kill them – I think the old method of scalding them with hot water seems to have gone out of fashion. The way I do it is to get the maggots and riddle off any maize or sawdust so they are totally clean. Then I pop them in a plastic bag, remove all the air, tie it off and pop the bag in the freezer.
It’s important not to freeze them for too long, as they can deteriorate if you do. I usually prepare them two days before I’m fishing and take them out the night before to defrost.