I would advise you to always have your bird checked by an Aviary Vet. Beaks are like finger nails, they grow and you have to be careful that the beak does not get over grown. If your Macaw is a chewer and most are, you should not have an issue but if your bird is not, you have to watch to make sure that the beak does not get to close to the crop, if you believe that you have an over grown beak, getting it trimmed is the correct thing to do. As far as polishing the beak, I have never heard of this. Like the previous member wrote, if the bird is in good health, polishing is not needed. If you want to make the beak shiney, you can always use 100% pure Aloe Vera just don't get it to close to the opening of the nose. Aloe is very safe for birds. I will sometimes use it on my birds after a shower or during the winter months, i use it on their feet. Both my boys seem to love it. Best of luck Joe