Have used cardboard with news paper for the last 2 years

I would use cardboard, being careful to keep it dry.

You don't want moisture to damage your cannas,
& plastic sometimes "sweats".

Thank you both. Thats what I thought just wanted to be sure.

No containers,they will hold in moisture,and the tubers will rot. Store under a thick blanket,so they will stay dry.

I just pile them into an old cardboard box or paper bag and stick them in my attic. They stay cool and bone-dry and store beautifully.

The only problem I have had was with the thin, ropey rhizomes of C. 'Omega', which shrivelled quite a bit but enough survived to to replant in the spring. (Unfortunately last year I left them in the ground over the winter and they did not make it).

I dug and stored my Cannas in a BIG plastic tub from KMart last year. I washed the dirt off the roots and threw over 200 rhizomes in the container. I stored them in the warm house. Warm, as in 72-78 degrees (wood furnace heated)They all came thru fine and flowered this Summer.

oops... I forgot to mention that I did NOT put a lid on the plastic storage tub!!