Google suggests you can actually cook pork shoulder on the grill, nice and slow

Which would be nice in the heat. Oh, if only Stop and Shop hadn't decided it was out of stock of all charcoal. (And also all yogurt. I had substitutions on, I don't believe they could not have found anything to substitute for both of those!)

We do have charcoal in the basement but... well... it's been in the basement. Can charcoal go bad from being in a damp and humid environment for a year or two or three?