I've always used the Calphalon cleaner as that is what they recommend. You'll need some elbow grease with that cleaner, but it does the job.
Teresa

I use Bar Keepers...just make sure to rinse everything well b/c a powdery film can result if you're not thorough. Of course this happens everytime my husband does the dishes :)

I also use Bar Keeper's Friend with a green scouring pad. The pads are color coded and the green ones are very aggressive. Calphalon recommends BKF for Calphalon One but I also use it for all my other Calphalon when needed. Never had a problem with it and it really works very well.

Bar Keepers Friend also makes Copper Glo which needs a little less elbow grease.

What gets the white powder looking discoloration on the inside of the Magnalite Aluminum Pots?