You should leave the leaves alone, so they can soak up the sunlight, to help build up the nutrients for next years flowers.

You should also give them a feed now, to also help build up for next year.

Once the leaves start going yellow, then you should remove them.

If you need the container they are in, then you could always plant them in the garden.

Wait until they have died down and are dormant before transplanting.

Totally agree with Alex. even the local council mows round the daffodils until the leaves have died back completely.

If you really need the containers can you put them in a spare piece of ground, or transfer them in the clump to a different container - doesn't have to be pretty as long as it has a drainage hole. Then if you want to you can dig them up again and store them somewhere dry cool and mouseproof.