One of my favorite household helpers is vinegar. It has so many uses around the house. Aside from the usual cooking uses you might think of, it is also useful in many cleaning applications. Vinegar can be used in mop water. Vinegar can be used as a neutralizer for lye spills and splashes during soap making. And my favorite use for vinegar is in the laundry. It is a great fabric softener and static reducer. It also helps remove soap residue from your clothing. Here's my formulation for laundry use.
1/4 cup vinegar
5-6 drops essential oil (I use Tea Tree most of the time; however, lavender, eucalyptus, and rosemary are excellent choices as well)
1/2 cup water
Pour into your fabric softener dispenser the same as you would chemical fabric softeners.