Sheer curtains

I need information about polyester sheers that are hung behind linen
curtains in a historic house. I think the sheers are only about 20
or so years old. The fabric is a patterned polyester with a cotton
thread stitching. The problem is that they are very dingy and gray.
Is there any way to brighten and whiten these sheers? Thank you,

Christine Cross
Curator of Collections
Ten Chimneys


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                  Conservation DistList Instance 15:4
                  Distributed: Tuesday, June 19, 2001
                        Message Id: cdl-15-4-010
                                  ***