Okay, so this might sound a bit crazy. I work at Starbucks... and I want to make a Starbucks themed tank using various mugs and cups from Starbucks. They are all plastic or ceramic, so I would assume they are alright to put in the tank, but do I need to do anything specific to them to make sure they are fish-safe? I have some reeeeeally cute ideas including a "spilled" cup of coffee made of brown rocks or gravel. But yeah... how do I make non-aquarium things aquarium safe?