Car has mold on leather
Bleach kills mold,try anything with bleach in it,or make your own for a spray bottle
Absolute worst thing to use on leather, bleach doesn't kill mold unless it's on non-porous surface and will completely ruin leather as well as weaken sewn areas causing eventual splitting. "There are a number of chemical ways to remove mold from car seats and most people would jump for the bleach or ammonia based products to kill it and clean the area, however these will not work!
First of all, those type of products will stain or bleach your car seats, carpet and interior. They also do not work well on porous surfaces and will damage the color of your car’s interior.
Second, they will not kill the mold! They will change its color and may kill some of the surface mold initially, however, mold spores will still survive and even worse, mold will actually thrive and grow on ammonia, so it will get worse than when you started!"
Bleach only kills mold on solid surfaces and will ruin leather not only leather itself but all the bindings anywhere it is sewn. Anything that is porous you should use straight vinegar here is some good help/info. to use, I've done this on several classic cars after they had been sitting in garages,barns. Then use good leather conditioner to soften it back up and keep it from cracking/peeling/splitting. https://wheelsguide.net/remove-mold-car-seats-interior/ conditioning "A good rule of thumb is every three months. If the car is frequently used or spends lots of time in the sun, every two months may be a better timetable. On the other hand, if the vehicle is used gently on an irregular basis, cleaning and conditioning every six months should be sufficient." use either of these cleaner/conditioners they are excellent Chamberlains Leather Milk or Leather Honey great on handbags,belts & shoes/boots,even horse tack too
Lynn is right about the bleach that it will ruin the leather. Do not use!