This might sound nuts to some, but for Asian people, this is one more thing "rice" can do.

After taken the seat out, lay big paper towel to cover the area. Then put some good amount of un-cooked riceon top of it. Leave it for couple of days.

If the rice become soft, take out the whole thing lay another set of paper towel and repeat the whole process until the rice stay dry for a day.

Rice will absorb water so quick, plus, it will absorb all un-wanted smell too! Do the same thing with the seat, then finnish off with leather care product.

 

This thread reminds me of high school when my friend and I were catering a party for a friend's dad. After picking up several hundred dollars worth of Mexican food (in several those large, stainless steel buffet trays with only tinfoil on top), my buddy stopped too abruptly in his station wagon.
The sloshing noise we heard next was 3 gallons of black beans (and the soupy liquid they are usually served in) that launched off the rear bench seat, onto the floor, and formed a gorgeous, liquid black wave that flowed forward under the front seat, eventually cresting and breaking in the front passenger footwell. I lifted my feet into the air just in time to avoid getting drenched in beans and bean juice.
We were horrified and the dad throwing the party was PISSED.
The seats had to be removed from the car, but despite the detail shop's best efforts, the "BeanMobile" never lost it's spicy, musky smell.
Wherever that car is today, be it a scrap heap or what, I guarantee it still smells like black beans.