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.
How to preserve pumpkins & gourds to make them last longer. First, give 'em a bath! In a solution of bleach water, 1 part bleach to 10 parts water. Let 'em hang out in there for a little while. If you put the stems down, they won't bob up. Then dry them off and buff them with some Vaseline.