Turn Tiles into Coasters by Stamping them with Paint! Have some Christmas stamps? Get some inexpensive tiles. Probably after they are thoroughly dried would be smart to give a couple coats of a clear sealer, so ink lasts.
Only issue with these mods, folks forget those tanks have to be inspected every Years. Make sure stamped date is still visible and not near expiration. Last thing want to do is customize tank that is not refillable
Here's a little tutorial on how to make your own rubber stamps. I like to use a stamp carving block as this allows you more freedom with the size. It can also be nice to affix your stamp to a woodblock to make stamping easier.