I was wondering what all of you out there prefer in the way of gondola or hopper car loads. I plan to have a coal mine servicing a power plant as part of my layout and I was wondering if it is worth the potential cleanup hassle to run live loads in the hopper cars. I have two of the planned 10 hopper cars (Athearn Undecorated 40 foot/4 bay hoppers) and I am experimenting using Aquarium carbon as a live load for them. It so far is working well in my short train I am currently running on a simple track loop on the floor. I don't want to permanently ruin these cars by gluing in a dummy load but I know how to make removable loads using the water/glue mix method and I am thinking of going that route possibly. I don't want to have to be cleaning up coal spills during my operation sessions once I get my layout running well but at the same time it would be nice to run the more realistic looking live loads in the hoppers. I can't decide, what do all of you prefer?