Thank you everyone for your suggestions and sharing your experiences. I followed your good advice and ordered a new eggcrate seat cushion with a waterproof cover.
I would buy a new one and a waterproof pad and start over. That foam once saturated will not dry. As it is now you are also going to have to use vinegar for the odor it must have.
Our son is very young and frequently has accidents and his pee smells terrible. The only thing that worked was using liquid detergent for soap, and filling the cup for the “liquid fabric softener” with WHITE VINEGAR. It neutralizes the enzyme in the pee, and gets rid of the smell. If still bad after a first wash, wash it again with more vinegar.
I used to have a male cat who would spot pee on a foam pet cushion when he felt anxious. That foam's pretty tenacious. There are pet urine odor removers you can pre-soak with (urine's urine, right?). Oxy-clean powder at 3-5 x the regular strength as a pre-soak can work too. I'm hoping you can just spot treat. I used to prop the foam up across a doorway and aim a fan at the cleaned spot overnight, otherwise it wouldn't dry well. You can get the eggcrates at the dollar store pretty cheaply, so if it's a lost cause just get a new one along with a waterproof cover.
Is it a bed cushion? Full, twin,etc. Or a seat cushion.
I may just replace if on a bed. And to save the next one from getting soiled, put it under a water repellant mattress cover directly on top of the mattress. Or wash in a bathroom tub.
If smaller, I would soak it first in some Vinegar and water. Then add some very very small amount of an HE detergent. Its suppose to be low sudsing. Those egg crates are like sponges and will be hard to rinse out. Rinse in cold water (hot makes more suds) with vinegar to help cut down on suds. You may have to rinse more than once. Dry outside in the Sun. Dryers tend to bring out the smell again. Try to find a water repellent cover so you don't have to keep washing.
Unless this is a very thin cushion in my experience it is very difficult to completely dry foam cushions, the core holds moisture even after days of sun exposure and you end up with stinky mildew. If it's a write off anyway I guess there is no harm trying, I would hand wash in a laundry tub and then spin dry in the washing machine. And yes to the waterproof cover, I paid for extra covers for all my mom's wheelchair cushions.
With all respect, my guess is your time has value and this is not the most pleasant of tasks. SInce these are usually made of foam, I'd be concerned of having an even bigger mess if they disintegrated in the washer or dryer (it it tolerates that). I'd be looking to see if they make washable ones, or if you know it is than go for it...otherwise I'm guessing a laundry tub sink filled with water mixed with a little detergent and squishing it through, rinsing well, and then squishing out as much water as possible and letting it air dry flipping occasionally on a towel. Maybe a waterproof pad/cover over it for the future?
https://www.amazon.com/Best-Price-Mattress-Memory-Infused/dp/B07PYDS6PK/ref=asc_df_B07PV613WQ/?tag=&linkCode=df0&hvadid=343991370144&hvpos=&hvnetw=g&hvrand=10951381319478613071&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9028940&hvtargid=pla-696278198835&ref=&adgrpid=72020986274&th=1
Our son is very young and frequently has accidents and his pee smells terrible. The only thing that worked was using liquid detergent for soap, and filling the cup for the “liquid fabric softener” with WHITE VINEGAR. It neutralizes the enzyme in the pee, and gets rid of the smell. If still bad after a first wash, wash it again with more vinegar.
I'm hoping you can just spot treat. I used to prop the foam up across a doorway and aim a fan at the cleaned spot overnight, otherwise it wouldn't dry well. You can get the eggcrates at the dollar store pretty cheaply, so if it's a lost cause just get a new one along with a waterproof cover.
I may just replace if on a bed. And to save the next one from getting soiled, put it under a water repellant mattress cover directly on top of the mattress. Or wash in a bathroom tub.
If smaller, I would soak it first in some Vinegar and water. Then add some very very small amount of an HE detergent. Its suppose to be low sudsing. Those egg crates are like sponges and will be hard to rinse out. Rinse in cold water (hot makes more suds) with vinegar to help cut down on suds. You may have to rinse more than once. Dry outside in the Sun. Dryers tend to bring out the smell again. Try to find a water repellent cover so you don't have to keep washing.
And yes to the waterproof cover, I paid for extra covers for all my mom's wheelchair cushions.