Cleaning sofa cushions

[PumpkinKlNG]

I have a sofa with some large scatter back cushions, for whatever reason the actual seat cushions can come off to be washed but these ones have no zip and can’t be washed in the machine, they are too large to fit inside, what’s the best way for me to clean them?

I used my vax steam cleaner, can be made into a hand held version with a smaller nozzle with a little cover and I steam cleaned my sofas so they didn’t smell doggy.