I'd kinda like to do a couple of Jack O' Lanterns this year, but I havent done any for YEARS (like 20!) How long do they last once you open up the pumpkin? I saw one website reference that said like 2 days?!? Is that true? Means I'd have to carve them the Saturday or Sunday Morning before Hallowe'en. Can anyone give me some practical limits on how long I can expect them to last?