How to Clean a Car Seat. Remove the cover from the car seat. The user guide contains instructions for both removing and replacing the cover. Hand-wash the cover using cold water and mild soap. Don’t use bleach or machine wash the cover. Lie flat or line dry to prevent the cover from shrinking. Don’t machine dry or iron Place the cover in the washing machine on “cold” and “gentle” with a mild detergent no fabric softener. 6. Once it’s washed, place the cover over a chair or your dryer to allow it to air dry completely before putting back on the car seat form.I have washed DD’s car seat cover in the washing machine in cool water w/ a touch of our regular laundry detergent (Country Save). Then If you cannot remove the cover to run it through the washing machine, you’ll have to wash the whole thing by hand. Use a sponge and a mild detergent to clean the entire cover.It can be a lot easier to clean a car seat cover than the car seat itself. Most car seat covers can be put through the washing machine but depending on the The question you are left with is, ‘how do I clean this thing?’. DO NOT: ever, ever, ever place your child’s harness in the washing machine.So iv taken the cover off the base (1st stage) ready for cleaning for no.2. to shove it in the machine for a good scrub what do you think/wwyd?