Gas Cylinder Pads - rust ring on floor issue

We have several gas cylinders stored on tile floors that are approximately 52" tall and 9" diameter with large collars that keep them from tipping. Unfortunately, the tanks tend to leave rust rings on the floor. Our gas company says that there really is nothing designed to place the tanks on. Have any of you experienced this and have devised some ingenious way of resolving this issue? Please let me know. We have some FRP board that would work as a giant coaster but I hate to "Mickey Mouse" this if there's a better idea.