Forget about second-hand smoke; one company wants your second-hand cigarette butts.   TerraCycle, a company that specializes in upcycling hard-to-recycle materials, has joined forces with San Diego based nonprofit RippleLife in an effort to repurpose cigarette filters. The effort is sponsored by Santa Fe Natural Tobacco Company, which apparently wants to do its part to keep its hipster customers from littering up cool, gentrifying neighborhoods nationwide.   Funded by donations, RippleLife became one of the first grassroots organizations to offer incentives to recycle cigarette butts 18 months ago, but they didn't know what to do with all the butts they collected. Enter TerraCycle, which now offers a way to recycle large quantities of butts by turning them into plastic.   Contrary to popular belief, cigarettes aren't biodegradable because of their filters, which are made of cellulose acetate. It is this acetate that is upcycled into plastic shipping pallets, says Stacey Krauss, TerraCycle's spokeswoman.   "This issue is way more enormous than I ever thought," says Chris Baffico, founder of RippleLife. "If you could show up and clean up 2,000 butts and five or six days later they were right back, you'd see what I mean."   Cigarette butts are some of the most commonly littered materials, with 65 percent of them not making it into trash cans, according to Keep America Beautiful.   "You don't have to walk or drive very far to see that smokers often discard cigarette waste in ways that litter the environment," says Cressida Lozano, head of sales and marketing for SFNTC.   Anyone can participate in this recycling campaign: simply collect the butts in a plastic bag, put that bag in a shipping box, and mail it off to Terracycle. But, as with any new initiative: Will people actually do it?   Terracycle's next coup: Turning dirty diapers into park benches. No kidding.