Baby car seat cleaning, and gum, vomit, mold and other upholstery stains

A child seat is crash equipment first and upholstery second. "The components must withstand high forces and repeated use to keep kids safe in the event of a crash, so you don't want to use any cleaners or disinfectants that may compromise any of the seat's components in any way," says Jennifer Stockburger, a certified child passenger safety technician at Consumer Reports. Your own manual wins wherever it differs from the table.

CDC's vomit cleanup is gloves and paper towels, then a bleach solution "with a concentration of 1,000 to 5,000 ppm (5 to 25 tablespoons of household bleach [5% to 8%] per gallon of water)" or an EPA-registered disinfectant, and soiled laundry washed "with detergent and hot water at the maximum available cycle length" and dried "at the highest heat setting" (CDC). A child seat's makers say the opposite: cold water, no bleach, no dryer. Which rule applies where:

Mold in a car means water got in, so dry the source before you clean anything: find the leak (how to get mildew smell out of a car), pull the water out and get air moving. Cleaning a surface that stays wet only brings the mold back. Then, on every material:

• Protect yourself. EPA suggests an N-95 respirator, gloves to the mid-forearm and goggles without vent holes, and says a homeowner can usually handle an area under about 10 square feet (EPA).
• Remove it, don't just kill it. "Dead mold may still cause allergic reactions in some people, so it is not enough to simply kill the mold, it must also be removed" (EPA). EPA does not recommend bleach "as a routine practice during mold cleanup", and Consumer Reports keeps bleach out of car interiors because it can damage the upholstery (Consumer Reports).
• Dry it within two days. Dried "24-48 hours after a leak or spill", in most cases mold will not grow (EPA).
• Know when to replace. "Absorbent or porous materials, such as ceiling tiles and carpet, may have to be thrown away if they become moldy" (EPA). In a car that means the carpet pad, seat foam or headliner fabric.

What each surface tolerates:

Not in the sense the word promises. CDC separates the steps: cleaning "removes most germs, dirt, and impurities", sanitizing "reduces germs to levels public health codes or regulations consider safe", and disinfecting "kills most germs" (CDC). Sanitizers and disinfectants are antimicrobial pesticides regulated by EPA (EPA), and a device's EPA establishment number "does NOT indicate that the product has been reviewed for safety or efficacy by EPA" (EPA).

"Kills 99.9%" lines rest on lab work. In one peer-reviewed test, a saturated steam vapor system inactivated every pathogen tested within 5 seconds, on porous clay test surfaces, in the author's own testing lab (Tanner, 2009). A car seat is fabric over foam, which that test did not cover. Steam is a good cleaning tool for hard surfaces; a "sanitized" promise is a claim to ask about. At home, CDC says sanitizing or disinfecting "is likely not needed unless there are sick people in your home" (CDC).

How to disinfect a car interior without damaging it

After a stomach bug, or before passing a car on, disinfecting is a second step, never the first:

1. Clean first. "Clean surfaces before you disinfect them" (CDC); EPA's steps say to wash a visibly dirty surface with soap and water first (EPA).
2. Use an EPA-registered product, by its label. Find the EPA registration number, check the label's "use sites" and "surface types", and follow the contact time: "The surface should remain wet the whole time to ensure the product is effective" (EPA).
3. Check it against your car. GM tested a short list of disinfectants for its interiors, among them unscented, bleach-free Clorox disinfecting wipes, and says scented or bleach wipes "can cause chemical attack on interior surfaces". Test any product in a hidden spot first: color on the wipe, or a changed look on the surface, means stop. For most surfaces GM still recommends mild soap and water (GM 06-00-89-029T).
4. Spend it on the touch points. Consumer Reports lists the "steering wheel, door handles, shift levers, any buttons or touchscreens, wipers and turn signal stalks, passenger and driver door armrests, grab handles, and seat adjusters", calls soap and water "safe and effective", and rules out bleach, hydrogen peroxide and ammonia-based cleaners (Consumer Reports).

What stays off three surfaces. A product that must stay wet for minutes is a poor match for materials carmakers say to keep dry. On leather, high-alcohol, acid or alkaline products can make it fade "or the surface may get stripped off" (Hyundai), and it should not be soaked (Mercedes-Benz). On screens, Tesla allows a display cloth and no cleaner or alcohol-based gel (Tesla); other makers differ, so your manual decides. On Alcantara, the maker's care page gives water, a soft brush and its own named products, and names no disinfectant (Alcantara). The steering wheel, step by step: how do I disinfect a steering wheel without damaging it?

What steam does well in a car

Steam is heat and a little water. Its job is loosening grime from places a cloth can't reach, with little or no chemical:

• Hard plastics, vents, cup holders and seat rails. Sticky drink residue and grime in seams and textured plastic soften under the nozzle and wipe off with a microfiber, without spraying a cleaner into the louvers.
• Cloth seats and carpet, before extraction. Steam loosens the soil; the extractor then pulls the water and dirt back out, and GM's extractor specification is built so "the fabric surface is not wet more than is necessary" (GM). Steam alone leaves the loosened dirt in the fabric.
• Not on electronics. Keep the nozzle off screens, switches and the instrument cluster: Hyundai's manual says never to let water or other liquids reach electrical and electronic components (Hyundai).

What steam does not do is turn a clean into a disinfection: that takes a registered product used as its label says, as in how to disinfect a car interior without damaging it.

After hot-water extraction, cloth seats are usually dry to the touch within a few hours, because the machine pulls most of the water back out (car seat and carpet shampoo). A soaked DIY job takes longer. Two limits matter:

• The front passenger seat. Many cars have an occupant sensor in that cushion. Hyundai: "Make sure the seat has been completely dried before driving the vehicle", or "the airbag warning light may illuminate or malfunction" (Hyundai).
• Mold. If anything is still damp after a day, move air through it: EPA's window to dry wet materials is 24 to 48 hours (EPA).

A fabric protector goes on only once the seat is "dry, clean and free of product residues", and its effect takes up to 24 hours to develop (Koch-Chemie).