http://www.forrestrace.com/glass-mosaic-5/

How do I clean discolored white linen on a vintage crushed glass mosaic wall hanging?
Some of you will remember those 60′s crushed glass mosaic wall hangings. The back ground looks to be off-white linen, but it is discolored and has some finger smudge marks.
Any ideas?
thanks.
the same people who restore paintings
How to Make Glass Mosaics : How to Glue Glass Mosaics