Vintage linens, even well cared for or newly washed linens, sometimes have yellow spots or stains that are often caused by a poor rinse. To get rid of the majority of these stains mix:
1 Gallon warm water (warm enough to melt the soap)
2 TBS of GRATED Ivory Soap (buy it by the bar and use an old food grater to shave off 2 Tablespoons)
1 TBS Bleach Mix
Stir and melt the soap then let cool until liquid has gelled a bit. Apply the gel to the stain. Make sure to test a small area first before using. As with all vintage pieces, rinse very well, over and over, to remove every trace of the soap.