I'm not a cleaning expert, and I'm sure others will chime in, but here is what I'd do. Given it's age, I assume it's some natural fiber and the stain is a food stain.
First, I'd take a corner of it and drape it in a dish of luke warm water (on the cold side) for awhile (6 or 8 hours) to see if there is any bleeding of the colors. Having some color in the water, if it's not too much, might be expected but I'd worry about the design getting muddled.
If that goes OK, I'd put water in a large container - a bath tub maybe - and disolve Ivory Flakes in the water. I'd carefully layer the whole thing into the water with the stain where I can see it. I'd leave it several hours, keeping an eye on it. If the stain isn't disappearing, I'd carefully rub a little bit of salt into the stain and see if that helps. Salt and water produces acid, and the acid might eat into the stain.
At that point I'd hand agitate it to wash the whole thing, rinse the soap out with a vinegar rinse, rinse the vinegar out with plain water, and spin dry in the washer. I'd hang it to dry until just damp and iron it.
If the stain is old and has been ironed in, it's probably well set and nothing will work. I have been able to remove old stains by just soaking long enough, but it's really good if the stain hasn't been heat set by a dryer or ironing.