Sunshine Cleaning (R) ***

Quirky families that employ unorthodox methods of dealing with trauma have become the backbone of the indie comedy/drama these days, whether you're talking about the defiant goofiness of Napolean Dynamite or the twisted black humor of Little Miss Sunshine. Sunshine Cleaning is more sentimental than either of those, owing to a backstory that seems brewed in some hellish Lifetime movie cauldron. But its overall ability to balance humor and drama, attention to emotional detail and a few winning performances outweighs its maudlin tendencies.

Set in Albuquerque, the film focuses on the dead-end lives of two sisters. Former high-school cheerleader Rose (Amy Adams), prone to repeating the list of affirmations stuck on her bathroom mirror (``You are strong!''), is a single mom, working for a maid service and sneaking around with a married cop (Steve Zahn). Her younger, ne'er-do-well sister Norah (Emily Blunt) can't keep a job and still lives at home with their dad (Alan Arkin, rapidly becoming The Official Quirky Old Guy of the indies). If you're unsure who's the good girl and who's the rebel, know that Norah has tattoos and wears clunky, funky necklaces.

When her odd little son Oscar (Jason Spevack) gets booted out of school for licking things in class (including his teacher), Rose decides she needs to make more money to pay for private school. Conversely, you could tell your kid to quit licking things instead of acting like it's OK, which seems cheaper and less of a health hazard, but then we'd have no impetus for Rose to find a new job.

On a tip from her boyfriend, she starts a business that pays much better than scrubbing toilets or washing dishes: Biohazard removal, which involves cleaning bloody, brain-spattered crime or suicide scenes or places so filthy that maggots have taken up permanent residence. For moral and physical support -- lugging a blood and/or body fluid-soaked mattress around by yourself is no picnic -- Rose enlists the reluctant and unreliable Norah.

Sunshine Cleaning doesn't shy away from the goriest aspects of the job -- there's a reason the work pays well -- so there are more than a few gross-out moments. The film's success lies in the delicate way it shows how the job affects the sisters emotionally. Tough-talking Norah finds a stack of photos of a little girl in a dead woman's apartment and tracks down her grown-up self (Mary Lynn Rajskub of 24). Rose's eyes light up at the prospect of a job cleaning up after a suicide, but the reality -- a shaken elderly widow waiting outside her house to let in the cleaners -- hits hard, especially in light of the sisters' past, which is revealed as the movie chugs along.

Adams, who was nominated for an Academy Award for her role in last year's Doubt, exhibits an appealing vulnerability. Rose knows she's a victim of her poor choices, but she refuses to give up the notion of bettering herself, even if she has to paste on a fake cheerleader's smile to do it. Better still is Blunt, light years from her glam The Devil Wears Prada role. She makes Norah more than a wild-child cliché, although the plotline involving Rajskub feels somewhat unfinished.

Still, Adams and Blunt make thoroughly convincing sisters, and they effectively drive home Sunshine Cleaning's message: Life is messy, and family politics can be dirty, but we always have the opportunity to clean ourselves up.

Cast: Amy Adams, Emily Blunt, Alan Arkin, Steve Zahn, Mary Lynn Rajskub.

Director: Christine Jeffs.

Screenwriter: Megan Holley.

Producers: Jeb Brody, Peter Saraf, Marc Turtletaub, Glenn Williamson.

An Overture Films release. Running time: 102 minutes. Language, disturbing images, some sexuality, drugs. In Miami-Dade: South Beach, Intracoastal; in Broward: Gateway; in Palm Beach: Palace, Shadowood, Delray, Parisian.