For about 10 years, I've been making my own laundry-pretreatment. I found the recipe in the Tightwad Gazette. To make it easy on everyone, I buy a bottle of spray and wash and proceed to use it up. That only takes a week or two around here. (Yes, I spill on everything and everyone)
Then, I use the original container to make another batch.
With a funnel, pour in the following ingredients:
1/2 cup of wisk
1/2 cup of white vinegar
1/2 cup of ammonia
Add water up to the top.
Put on the lid and shake 'er up.
The real question is: does it work? It does. It does smell a little different than the original, which could cause some problems. We once had a guest who asked to do some laundry. Later she told me that she couldn't use the spray and wash because, "it smelled like vinegar!" HA... that's one way to keep 'em out of your special stash of spray and wash!
Make your own.