Cleaning upholstery on vintage chair

I have a vintage Hickory Chair chair. The cushion is removable and has a goose down insert. The fabric on it (does not match the fabric on the link) is in good shape, but needs cleaning. It was pulled off a box truck that had been sitting for years a tree branch fell on a poked a hole through it. The chair was never rained on, thankfully, but it smelled of mildew. The smell is mostly gone, unless you bury your face in it, but there is some minor staining on the arm rests, seat, and back.
With fabric being attached to most of the chair is it safe to take the hose attachments of my steam cleaner and clean it this way?
Whats the best way to clean the down insert? I fear putting it in the washer because of the age.

How do you keep the caning from becoming brittle?
I hit it with some howards today but I dont know if that really conditions it


https://www.chairish.com/product/265219/hickory-chair-vintage-mahogany-sheraton-armchair

 

Hi,
I would put the insert cushion in a cotton pillow case and use a Dryel home dry cleaning sheet and tumble it for 10 to 15 minutes on low heat. The chair I would put in an ozone machine for 24 hours. It will smell wonderful.
greg

 

I think the chair will smell fine once the fabric is cleaned, its just cleaning the fabric...

And I dont have an ozone machine lol