A while back, we bought a set of sheets that felt soft at the store, but had a lower thread count than we usually buy. We brought them home, washed them, and slept on them. Quickly, we learned that these sheets weren’t washing well and were not as soft as they first seemed. So I went searching for a way to make them softer, instead of replacing them and making a donation to Goodwill.
I found a couple of pages that gave me some ideas. On this page, the ideas of vinegar and milk are mentioned, along with some others. I just finished trying the vinegar option. I put a half cup of vinegar in the wash and rinse cycle. It did soften the sheets up a bit, but I wanted them softer. So now the sheets are in the wash with 1/2 cup salt in the rinse cycle and, due to what I read here, I put some (about 1/2 cup) baking soda in the wash cycle.
Now the wash is finished and the sheets are significantly softer. I’d assume that with continued washing in this manner, the sheets would get very soft. The powdered milk method does sound interesting, too. I can’t wait to put the sheets on the bed and see how they feel!