Your question is indeed a challenge! Can I first ask something about your interest in textiles? I note that you list your interests as: 'hmong/miao textiles'. Do you have a collection of them and does it matter to you whether they are special examples of a particular group? Do you display them? Are you interested in using them in a design setting - hence the 'mounting'?
The answers to these and other questions - which are not popping into my mind at the moment - have influence on how you treat these skirts. If these skirts really are as old as 1930s and they are basically fine examples then cleaning them - and causing any resulting damage is quite worrying. If they are good ones then I suggest that you need specialised conservation cleaning.
You mention that the skirts are dusty. Some carefully vacuming with gentle suction can remove some of the dust and dirt. A gentle brush - but be careful not to damage the silk - can also help.
Re-pleating a Hmong skirt is quite a challenge but a Green Hmong one is, I think, easier than some others. The skirt needs to be laid out flat and the skirt carefully pleated and, at the same time, parallel threads put through at intervals which will be drawn up to hold the pleats in place and 'set' the pleats. The technique is rather like preparing smocking if you have ever done that? See a photo of a Green Hmong woman gathering a skirt in a village near Chiang Mai in Thailand
http://www.tribaltextiles.info/Gallerie ... /BHE15.htm When the skirt has been gathered it should then be rolled up carefully and tightly and tape tied around it - see this Flowery or Variegated Hmong woman in Vietnam just about to untie a skirt for me
http://www.tribaltextiles.info/Gallerie ... namE02.htm
If the skirt is damp when pleated then, if ever the skirt dries and hemp is the very devil to dry, then the pleats should stay in reasonably well.
It would be a big risk to actually wash the skirt because of the silks and the colours might run - especially the red and orange which can be very fugitive colours. If you see this photo of the same Flowery Hmong in Vietnam
http://www.tribaltextiles.info/Gallerie ... namE08.htm you will see a skirt hanging out to dry. You will see some of the white parallel threads which have been left in and which will be used to draw up the skirt to hold the pleats back in. I would say that this skirt is a cotton rather than hemp one so is a much easier washing proposition and also there are no silk embroidery threads.
You do not indicate where you live. I don't know if there might be any Hmong communities living near you who might have older members who could help. I also don't know if you have any careful conservation workshops or museums. Some museums have days when people can take textiles for advice.
I shall be interested if we get any other suggestions from forum members. If you had a photo of the skirts we would be very interested to see it.
Good luck!!
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Pamela
http://www.tribaltextiles.infoon-line tribal textiles resource