Help?

So we have a bunch of sternos in the office left over from a breakfast. We didn't use them, but we don't have the tops for them either. We stacked them up, protecting 3 of them, but left the last one open b/c we had no choice. It has all but evaporated (3 weeks later!) but we've got 3 whole sternos that are just sitting on my windowsill being a fire hazard! Ideas, guys?