car seat cleaning

Did you buy it from someone you knew? Its one item I wouldn't buy secondhand as you don't know its history

www.childcarseats.org.uk/choosing-using/second-hand-child-seats/

If you don't know its history please don't use it. It may be missing bits or have damage bits under the cover or it may look like new but may still of been in an accident. There is no way of knowing. You can get a new seat for not much more than the money you spent. look at joie seats.

Which seat is it? The main issue with second hand ones is missing pieces or incorrect assembly, or seats so old they aren't approved any more. Accidents yes you run a risk of this, but I do think most people are honest enough they wouldn't resell a crashed seat. However, I would definitely inspect the seat very carefully. (Realistically I know people are going to buy second hand seats so I would rather give you advice about how to check the seat you have).

If you did not get a manual with it, download one from the manufacturer's website. It's important to read these thoroughly I also recommend watching official videos about the seat and comparing it to your version to check there aren't any parts missing and things like the straps are assembled correctly.

What kind of marks are on the plastic? This seems unusual so I would want to be sure they aren't stress marks.

Covers can generally be taken off and put into the washing machine on a gentle cycle at 30. Just be careful when removing straps in order to take off covers, ensure they are put back correctly. Taking photos as you undo the cover can help put them back right. This also gives you a chance to inspect the seat under the covers for any damage.

Oh, and do not use anything harsh on the harness, this includes things like bicarbonate of soda or bleach or vinegar.