I assume it is wool material we are dealing with so that throwing it in the washer is not a quick and easy option.

If so, finding out what the staining material might be would definitely help in determining if a drycleaner will be able to try to remove it without permanent damage. Failing that I would still try a drycleaning first to see what effects that might have, as long as you have someone you can trust to take care of the pleats (leaving the basting in might help in that regard, if it still has it). After a good drycleaning if the spots remain I would (after removing the basting) search out a good quality dye in a color similar to or darker than the stain, as you were considering, that is compatible with the material, and attempt to dye the stains into submission. If it is tartan material it will affect the lightest colors in the tartan far more than the others---if a solid color not so much an issue as long as you can live with the anticipated finished coloration. If that doesn't work, consider dyeing the whole thing in a very dark color---deep brown or black, which theoretically, if the dyes take to the fabric, should cover nearly all stains. Unless the stains have somehow altered the texture of the fabric as well, in which case you are stuck with that forever. Or unless the stains have altered the way the fabric is able to take up the dye, then you may end up with an invers type of stain--the stains would be lighter thanthe background. good luck. Keep us posted on your attempts and the results.

jeff