I would NOT WASH them before they are quilted. I've done a couple that someone washed before quilting and the material went every which way but straight. There were a ton of loose threads on the back from the fabric.
I'd air them out in the shade as many days as you can before quilting.
Don't laugh...but if necessary....wear a mask when you quilt to cover any offensive odors that are left.
Pictures please!
Nan