Since Jessica was born, I seem to have more impossible stains in our laundry to deal with. After a lot of trial and error, I have concluded that there are two types of impossible stains with different treatment methods for each.
1) Colored stains that will not come out (coffee, spaghetti sauce, red juice, etc.)
For this type of stain I take a bucket and fill it with cold water. Then I add about 1/4 cup of bleach and mix. Then I let the item soak in the mixture until the stain is gone or mostly gone. You want to make sure that you can monitor it while it is soaking because if the item is left in the bucket for too long, it will fade. Also you do not want to have to do this too often on items with elastic because it will break down the elastic over time. While this diluted bleach mixture can be added to the washing machine, I do not do that anymore because it does not allow me as much control over how much bleach each item is getting.
2) Oil stains
Cooking with oil can be messy, particularly if you have other things going on at the same time! I tried several things to get these stains out of one of my favorite shirts. I was just about to relegate it to the rag bin when I found this solution: rub dawn (or similar dishwashing soap) into the stain and allow it to soak for 30 minutes in hot water before washing. Amazingly it works!!!!
The only kind of stain I have not been able to find a way to treat is the hard spots under the arms of my husband's shirts. I have heard some ideas for preventing them, but I have not found anything that will get rid of them once they are there. If anyone else has heard of a way to get rid of these hard spots, please let me know!!!