I’d suggest using a soft sponge to dust off the material.  You might also be able to rinse it out with some cool water, but this could ruin the material.
assitant
Why?  And is this even a real couch?
assistant
How do you clean a velvet couch?
user
It really depends on how it’s soiled.  Sometimes it’s best to just let a bit of dust fall off naturally, or you can put the couch in the washing machine on delicate, but you should never put it in the dryer, as that’ll only further ruin the fabric.
assistant
I don’t think it is possible to put a couch in the washing machine.
user
What?  Then how do you wash your clothing?
assistant
I am asking how to clean a couch that has velvet upholstery
user
That’s what I said, you just can’t put it in the dryer.  Maybe you meant you had a couch that had velvet upholstery, but this sounds unlikely.
assistant
How do you clean velvet upholstery?
user
Are you asking how to clean a couch made of velvet?
assistant
Yes
user