Cleaning and fabric ID on 'A Caroma gown' 1930s dress

I really love the design of this dress, particularly how the bias cut fabric has been reversed in contrasting panels (hips and upper torso/sleeves) for a really smart subtle effect. The fabric is fairly lightweight with really good drape, cool and silky where satin on top, matte and crepe on reverse. Do you think it's likely to be silk or rayon from the type of dress and era? It's fully french seamed inside with a picot edge hem so I can't do a burn test. I think I'm pretty set on satin backed crepe for the fabric (although I did consider charmeuse), though it's not as 'crepey' as the 40s rayon crepe I've handled. Could that be because it's a diffferent fibre?
It has a strange strong chemical smell I want to get rid of, as well as several of the usual culprits: underarm stains, a couple of dark spots from liquid spills etc. It's light cream or oyster coloured at the moment but I do wonder if it was white originally. Or is this what they call candlelight satin?
The good thing is it is in good strong condition and doesn't need any repairs, so if I can clean it it will be ready to wear. Unfortunately I do remember reading people saying not to wash these fabrics. Has anyone tried? Is there any products I should or should not use in the water? is it prudent to spot treat areas before washing? I'd appreciate your thoughts.

 

satin back crepe... hmmm.... I think I wouldn't try washing it, but if you do maybe do the belt first and see how that works out? And old underarm stains on a white dress that is probably rayon - I bet they are there for good.

 

I'm not sure that it's crepe from your close ups, but I agree that crepe should only be dry cleaned. I've washed silk crepe and it shrinks but if you're very careful, you can gently steam and stretch it back to shape. Rayon crepe also shrinks but just rips when you try to reshape. As I said, I'm not sure that this is crepe though - and I would try to determine the fabric composition. If it's rayon, and not crepe, you could probably soak out the stains (remove the gorgeous buckle of course) but if it's silk, oxygen bleach can do bad things to it.

Lovely dress. I tried, but failed to find anything about Caromas Gowns, only found an '80s dress.

 

Coming back to this, I have only dared iron it - it survived a medium steam iron well. I did notice however that when the water dropped on it, the fabric became strangely stiffened like wax paper and fairly transparant. Does anyone recognise this as a particular fibre or fabric?