I saw a beautiful completed needlepoint picture on Ebay done in 1978 and selling for $10. I rescued it from the shame of being valued so little. It has multiple styles of stitching and came framed without glass. I'm afraid it is pretty dirty from just being exposed for all those years. I really don't want to take it out of the frame. Does anyone have suggestions for cleaning it? It looks like yarn stitching, but I don't know if it is wool or acrylic. Thanks in advance.