After you scoop out and carve your pumpkin, dip it in a large container of bleach and water (use a 1 tsp:1 gal mix). The bleach will kill bacteria and help your pumpkin stay fresh longer. Once completely dry, (drain upside down), add 2 tablespoon of vinegar and 1 teaspoon of lemon juice to a quart of water. Brush this solution onto your pumpkin to keep it looking fresh for weeks.
drop a silica gel packet (they come in shoe boxes) into a carved pumpkin and it prevents it from becoming mushy and moldy.