I would leave it open for a few days and maybe spray some Febreeze if that doesn’t bother you. I also try a Damp Rid when closed up, that may help. They have some that have different smells that aren’t too strong. http://www.walmart.com/ip/2367…..38;veh=sem
There are all sorts of ideas to reduce the musty smell, including using vinegar in water to clean it up. If you can air and/or wash the cushions, or at least the covers (on gentle, air dry, use thin plastic to help get the foam back into the covers), as well as the curtains (if any), that will help.
I would suggest that you do a thorough inspection to eliminate the possibility of mold or mildew. On our first popup, there was still a funky odor, even after washing the cushion covers. A few years after we bought it (well used), we had to renovate it and found hidden old mildew under one of the dinette benches. Once we took care of that, it was good.
I second the damp rid. One word of caution: Put the tub of Damp Rid in a bucket or dishpan. Just in case the Damp Rid container gets tipped over (like you forget to remove it before towing) The watery mixture inside won’t end up on the floor, and ultimately absorbing into your cabinetry. Because once in the cabinetry, the particle board swells and you can’t unswell it.
Thanks for all of the ideas. We are removing curtains and washing. Also wiping down everything and I will use vinegar. I am going to look at all the cushions and see if that may be source. Also will purchase damp rid. All of this is so helpful