Wild animals will nibble a jack-o'-lantern. Bleach, paint, and plastic decorations turns a pumpkin into contaminated food for wildlife. Squirrels, deer, raccoons, opossums, mice, chipmunks and birds will all eat a pumpkin. Most of them work at night and you never see it. None of them can detect bleach. That's not something an animal evolved to check for. They find food by smell, and a bleached pumpkin smells exactly like a pumpkin. Same goes for spray paint, glitter, and anything plastic you stuck in it. The thing bleach is supposedly solving isn't much of a problem anyway. A carved pumpkin gets five to ten days. That's the deal you made when you cut a hole in it. If you want a few more: one part white vinegar to ten parts water, soak it and spray it down nightly. Scrape the inside walls clean, since leftover pulp rots first. Keep it out of direct sun, bring it in on warm days, and use an LED instead of a real candle. Then when it's done, cut it up and leave it somewhere away from the road, or compost it. A rotting pumpkin isn't a failure. It's the last useful thing it does.