Commonly available at the grocery or hardware store.

I have been making and using only homemade laundry detergent since July 2008 and love it – works great and costs about a dollar a month! And the ingredients – aren't available in every grocery store or Walmart, but they aren't too hard to find once you know what you are looking for. The borax is the easiest to find and it is in most stores. Look for 20 Mule Team Borax. The washing soda is made by Arm & Hammer – and is NOT baking soda. One box of each of these will make a huge amount of laundry soap – a year's worth for some folks! The Fels Naptha soap may be a bit harder to find. You can also use Zote soap, homemade soap, any good cleansing soap except 'complexion' bars such as Dove. I add grated Ivory soap also because I like the scent. I have had good luck finding Zote in Big Lots stores. Zote and Fels Naptha are 'laundry soap' and can be found in the laundry aisle, not the 'bath soap' area. Your local store may start stocking these items if you ask. I have also known of folks who have Mexican groceries near them and can get a good laundry soap bar there – I don't remember the name of the soap though. I make 6 gallons at a time and store the soap in recycled laundry jugs. Also – you can cut costs on laundry softening by buying inexpensive liquid fabric softener, diluting with water, tossing in some sponge pieces. Use a sponge, squeezed partially dry in each dryer load.

Dede

If it were distilled vinegar, it should be all right.  You probably wouldn't want any organic material in with your laundry soap for long term storage.  Still, I don't think I'd want it mixed in just on general principles.  Too many chemicals sitting around without stabilizers.

But then I cannot articulate any real reason not to try it…  

I have been putting some white vinegar in my laundry soap, Cindy – the last 2 batches. Do not see any difference in the viscosity of the soap etc. Figured it would be another cleaning booster. Cheap enough to add in a bit. Hopefully it makes for cleaner rinsing. I love my laundry soap.

Dede

who has to make a new batch ASAP – down to a quart!

LOL I knew you were going to ask    Mine makes close to 6 gallons and I put in over a quart – maybe not a half gallon, but truthfully Cindy I don't remember exactly! I had a couple of partially filled gallon jugs left from making pickles and grabbed the least full one and dumped it in so probably quart and a half? 

dede